Weak measurement offers a powerful framework for probing nonclassical features of quantum mechanics,with anomalous weak values serving as operational signatures of contextuality.While the anomalous weak value verifica...Weak measurement offers a powerful framework for probing nonclassical features of quantum mechanics,with anomalous weak values serving as operational signatures of contextuality.While the anomalous weak value verification of quantum contextuality has been predominantly investigated in the single-photon regime and analyzed under approximation condition of infinitesimally small perturbation strength.This study releases the approximation condition and takes into account the impact of perturbation strength on the rigor of the verification.And the investigation on the verification of contextuality is extended to the multi-photon scenarios for observing the influence of the correlation between photons on the verification.Without the limitation of infinitesimally small probability of disturbance,anomalous weak values are identified as necessary for contextuality to emerge,thereby refining the criterion proposed by Pusey[Phys.Rev.Lett.113200401(2014)].In the multi-photon scenarios,the emergence of contextuality also depends strongly on both the photon number and the photon-number distribution state.In particular,contextuality is found to be maximized when the single-photon component dominates and the second-order correlation is lower.These results highlight the critical role of photon statistics in experimental tests of contextuality via anomalous weak values.展开更多
Transmission electron microscopy(TEM)offers unparalleled atomic-resolution imaging of complex materials and heterogeneous structures.However,high-energy imaging electrons can induce structural damage,posing a challeng...Transmission electron microscopy(TEM)offers unparalleled atomic-resolution imaging of complex materials and heterogeneous structures.However,high-energy imaging electrons can induce structural damage,posing a challenge for electron-beam-sensitive materials.Cryogenic TEM(Cryo-TEM)has revolutionized structural biology,enabling the visualization of biomolecules in their near-native states at unprecedented detail.The low electron dose imaging and stable cryogenic environment in Cryo-TEM are now being harnessed for the investigation of electron-beam-sensitive materials and low-temperature quantum phenomena.Here,we present a systematic review of the interaction mechanisms between imaging electrons and atomic structures,illustrating the electron beam-induced damage and the mitigating role of Cryo-TEM.This review then explores the advancements in low-dose Cryo-TEM imaging for elucidating the structures of organic-based materials.Furthermore,we showcase the application of Cryo-TEM in the study of strongly correlated quantum materials,including the detection of charge order and novel topological spin textures.Finally,we discuss the future prospects of Cryo-TEM,emphasizing its transformative potential in unraveling the complexities of materials and phenomena across diverse scientific disciplines.展开更多
We present a robust quantum optimal control framework for implementing fast entangling gates on ion-trap quantum processors.The framework leverages tailored laser pulses to drive the multiple vibrational sidebands of ...We present a robust quantum optimal control framework for implementing fast entangling gates on ion-trap quantum processors.The framework leverages tailored laser pulses to drive the multiple vibrational sidebands of the ions to create phonon-mediated entangling gates and,unlike the state of the art,requires neither weakcoupling Lamb-Dicke approximation nor perturbation treatment.With the application of gradient-based optimal control,it enables finding amplitude-and phase-modulated laser control protocols that work without the Lamb-Dicke approximation,promising gate speeds on the order of microseconds comparable to the characteristic trap frequencies.Also,robustness requirements on the temperature of the ions and initial optical phase can be conveniently included to pursue high-quality fast gates against experimental imperfections.Our approach represents a step in speeding up quantum gates to achieve larger quantum circuits for quantum computation and simulation,and thus can find applications in near-future experiments.展开更多
The magnetic properties and Kondo effect in Ce_(3)TiBi_(5) with a quasi-one-dimensional structure were investigated using in situ high-pressure resistivity measurements up to 48 GPa.At ambient pressure,Ce_(3)TiBi_(5) ...The magnetic properties and Kondo effect in Ce_(3)TiBi_(5) with a quasi-one-dimensional structure were investigated using in situ high-pressure resistivity measurements up to 48 GPa.At ambient pressure,Ce_(3)TiBi_(5) undergoes an antiferromagnetic(AFM)transition at T_(N)∼5 K.Under high pressures within 8.9 GPa,we find that Kondo scattering contributes differently to the high-temperature resistance,R(T),depending on the applied current direction,demonstrating a significantly anisotropic Kondo effect.The complete P–T phase diagram has been constructed,in which the pressure dependence of T_(N) exhibits a dome-like shape.The AFM order remains robust under pressure,even when the coherence temperature T^(*) far exceeds 300 K.We attribute the observed anisotropic Kondo effect and the robust AFM to the underlying anisotropy in electronic hybridization under high pressure.展开更多
We investigate distinct non-Hermitian skin effects(NHSEs)in real and Fock spaces induced by the interplay between the Hilbert space fragmentation and multiple non-Hermitian pumping channels.Using an extended Hatano–N...We investigate distinct non-Hermitian skin effects(NHSEs)in real and Fock spaces induced by the interplay between the Hilbert space fragmentation and multiple non-Hermitian pumping channels.Using an extended Hatano–Nelson model with next-nearest neighbor hopping and strong interaction as an example,we found that two fermions loaded in the lattice exhibit different real-space NHSE depending on the Hilbert space fragments to which they belong.Moreover,in the high-energy sector resulting from fragmentation,the two-particle-bound states form a one-dimensional lattice in Fock space,producing a Fock-space NHSE.At half-filling,richer patterns of Fock-space skin-like localization emerge for the different fragmented energy sectors and subsectors while realspace NHSE is suppressed by many-body effects.This study extends our understanding of the interplay between NHSE and Hilbert space fragmentation and provides detailed insights into their manifestation in interacting non-Hermitian systems.展开更多
We report on a Kerr-lens mode-locked(KLM)femtosecond Yb:CaYAlO_(4)(Yb:CYA)laser operating at a repetition rate of 1.04 GHz,pumped by a single-mode fiber laser.The laser delivers an average output power of 1.37 W with ...We report on a Kerr-lens mode-locked(KLM)femtosecond Yb:CaYAlO_(4)(Yb:CYA)laser operating at a repetition rate of 1.04 GHz,pumped by a single-mode fiber laser.The laser delivers an average output power of 1.37 W with a pulse duration of 109 fs.Potential improvements,including scaling the pump power,increasing the repetition rate,and further reducing the pulse duration,are discussed.This study contributes to the advancement of Watt-level GHz femtosecond laser generation and its applications.展开更多
The introduction of machine learning algorithms has revolutionized the design of invisible devices,particularly in the intricate domain of elasto-dynamics.In this study,we proposed a core-shell configuration to realiz...The introduction of machine learning algorithms has revolutionized the design of invisible devices,particularly in the intricate domain of elasto-dynamics.In this study,we proposed a core-shell configuration to realize elastic sphere cloaks driven by a Bayesian optimization algorithm to pinpoint the optimal configuration with high precision.Numerical simulations in solid and aqueous environments were performed to validate the cloaking efficacy of our design and the parameters identified by the algorithm.The results closely agreed with the theoretical predictions,underscoring the robustness of the proposed method.This approach provides new insights into the design of elastic wave invisibility devices and has potential applications in underwater communication and sonar detection.展开更多
This study systematically investigates the transport and point-contact Andreev reflection spectroscopy(PCARS) properties of Bi-doped BaFe_(2)(As_(1-x)Bi_(x))_(2) crystals under high pressures up to 8.7 GPa. The superc...This study systematically investigates the transport and point-contact Andreev reflection spectroscopy(PCARS) properties of Bi-doped BaFe_(2)(As_(1-x)Bi_(x))_(2) crystals under high pressures up to 8.7 GPa. The superconducting critical temperature(T_(c)) and upper critical field(H_(c2)) initially decrease with pressure but exhibit a local maximum around 2.9 GPa before further suppression, which can be related to the superconducting transition in the parent compound. The conductance spectrum is consistent with a two-band s-wave model, confirming multi-band superconductivity. The superconducting energy gaps and coupling strengths decrease monotonically with pressure, with the larger gap transitioning from strong to weak coupling. These results provide insight into the interplay between structural, electronic, and superconducting properties in isovalent-doped 122 Fe-based superconductors.展开更多
Manipulating and braiding Majorana zero modes(MZM)are a critical step toward realizing topological quantum computing.The primary challenge is controlling the vortex,which hosts the MZM,within a superconducting film in...Manipulating and braiding Majorana zero modes(MZM)are a critical step toward realizing topological quantum computing.The primary challenge is controlling the vortex,which hosts the MZM,within a superconducting film in a spatially precise manner.To address this,we developed a magnetic force-based vortex control technology using the STM system with a self-designed four-electrode piezo-scanner tube and investigated vortex manipulation on the NbSe_(2) superconducting film.We employed ferromagnetic tips to control the movement of vortex array induced by the tip's remanent magnetism.A magnetic core solenoid device was integrated into the STM system and a strong magnetic tip demagnetization technique was developed,providing a viable technical solution for further enabling single vortex manipulation.展开更多
Two-dimensional(2D)MoO_(2),a binary nonlayered material,has been extensively studied for potential applications in catalysis and electronics.However,the preparation of 2D MoO_(2) remains challenging.Herein,we report t...Two-dimensional(2D)MoO_(2),a binary nonlayered material,has been extensively studied for potential applications in catalysis and electronics.However,the preparation of 2D MoO_(2) remains challenging.Herein,we report the growth of 2D MoO_(2) flakes with rhombic morphology on the sapphire substrate via a chemical vapor deposition(CVD)method.Atomic force microscopy shows the CVDgrown MoO_(2) flakes with thin thickness.The CVD-obtained MoO_(2) with a stoichiometric ratio of 1:2 is verified using energy-dispersive X-ray spectroscopy.Scanning transmission electron microscopy(STEM)characterization reveals the high-quality,single-crystal nature of the CVDderived 2D MoO_(2) flakes.展开更多
The intrinsic antiferromagnetic topological insulators in the Mn-Bi-Te family,composed of superlattice-like MnBi_(2)Te_(4)/(Bi_(2)Te_(3))_(n)(n=0,1,2,3,...)layered structure,present intriguing states of matter such as...The intrinsic antiferromagnetic topological insulators in the Mn-Bi-Te family,composed of superlattice-like MnBi_(2)Te_(4)/(Bi_(2)Te_(3))_(n)(n=0,1,2,3,...)layered structure,present intriguing states of matter such as quantum anomalous Hall effect and the axion insulator.However,the surface state gap,which is the prerequisite for the observation of these states,remains elusive.Here by molecular beam epitaxy,we obtain two types of MnBi_(4)Te_(7)films with the exclusive Bi_(2)Te_(3)(BT)or MnBi_(2)Te_(4)(MBT)terminations.By scanning tunneling spectroscopy,the mass terms in the surface states are identified on both surface terminations.Experimental results reveal the existence of a hybridization gap of approximately 23 meV in surface states on the BT termination.This gap comes from the hybridization between the surface states and the spin-split states in the adjacent MBT layer.On the MBT termination,an exchange mass term of about 28±2 meV in surface states is identified by taking magnetic-field-dependent Landau level spectra as well as theoretical simulations.In addition,the mass term varies with the field in the film with a heavy BiMn doping level in the Mn layers.These findings demonstrate the existence of mass terms in surface states on both types of terminations in our epitaxial MnBi_(4)Te_(7)films investigated by local probes.展开更多
In unconventional high-temperature(high-T_(c))superconductors,the pair density wave state,an exotic superconducting order showing spatially periodic order parameter modulations with the period of several unit cells an...In unconventional high-temperature(high-T_(c))superconductors,the pair density wave state,an exotic superconducting order showing spatially periodic order parameter modulations with the period of several unit cells and translational symmetry breaking,has attracted broad attention.However,the superconducting pair density modulation(PDM)within a single unit cell has never been carefully investigated before.Here,using scanning tunneling microscopy/spectroscopy,we report the observation of PDM in monolayer high-T_(c) iron chalcogenide films epitaxially grown on SrTiO_(3)(001).The superconductivity modulations are characterized by the superconducting gap size and the coherence peak sharpness.Further analysis shows that the local maxima and minima in the superconducting gap modulation are centered at the crystallographic locations of the chalcogen atoms,revealing the breaking of the glide-mirror symmetry of the chalcogen atoms in monolayer high-T_(c) iron chalcogenide films grown on SrTiO_(3)(001).Our findings provide precise microscopic information on superconductivity within the lattice unit cell and may promote the understanding of unconventional high-T_(c) superconductivity.展开更多
Over the past few decades,angle-resolved photoemission spectroscopy(ARPES)has been one of the important tools to study electronic structure of crystals.In recent years,the spatial resolution of around 150 nm has been ...Over the past few decades,angle-resolved photoemission spectroscopy(ARPES)has been one of the important tools to study electronic structure of crystals.In recent years,the spatial resolution of around 150 nm has been reached through tight focusing of the light spot(nano-ARPES).At present,the lower limit of the spot size of the light on the sample has been reached.Another way to further improve the spatial resolution is through using apertures to only let electrons from a small area of the sample pass.With both back-focal plane and image apertures,the size of the selected area can be as small as 20 nm.Yet,without aberration correction,the maximum opening angle at the sample for 20 nm spatial resolution is usually smaller than 3°,making this method not suitable for nano-ARPES.As shown in this paper,a conventional aberration corrector,which corrects chromatic and third-order spherical aberrations,is not enough either.Only when the fifth-order spherical aberration is also corrected,the opening angle at the sample is large enough for nano-ARPES.In this paper,the design of a time-of-fight PEEM/ARPES/nano-ARPES instrument,which is currently under development at the Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area,is presented.The main point of innovation is a fiveelectrode electron mirror corrector,which is used to correct simultaneously chromatic,third-order and fifth-order spherical aberrations,resulting in 1 nm spatial resolution with~230 mrad aperture angle in PEEM mode.This makes feasible the method of using apertures to improve the spatial resolution of the nano-ARPES mode.A new design of the magnetic prism array(MPA)is also presented,which preserves the rotational symmetry better than the existing designs.展开更多
Topological superconductor islands are thought to be the building blocks of topological quantum bits.We produced single-crystalline VSi_(x)islands with well-defined side facets and island size more than 200nm using mo...Topological superconductor islands are thought to be the building blocks of topological quantum bits.We produced single-crystalline VSi_(x)islands with well-defined side facets and island size more than 200nm using molecular beam epitaxy on Si substrate heated to 950℃throughout the growth process.By means of scanning tunneling spectroscopy,we revealed dynamical Coulomb blockade and superconductivity on isolated islands and on islands being connected by superconducting wetting layer respectively.Bi_(2)Te_(3)films were further deposited on VSi_(x)islands.Robust and homogenous proximity effect induced superconductivity was observed on various facets of the Bi_(2)Te_(3)/VSi_(x)hetero-nanostructure.Furthermore,our high-resolution spectroscopy identified Bosonic mode excitations on the topological superconductor islands.These results may establish a playground for the vortex Majorana islands.展开更多
The kagome metals AV_(3)Sb_(5)(A=K,Rb,Cs)feature intertwined Dirac fermions,topological flat bands,and van Hove singularities(vHS)near the Fermi level,which give rise to a range of exotic,strongly correlated phenomena...The kagome metals AV_(3)Sb_(5)(A=K,Rb,Cs)feature intertwined Dirac fermions,topological flat bands,and van Hove singularities(vHS)near the Fermi level,which give rise to a range of exotic,strongly correlated phenomena such as charge density waves(CDW)and superconductivity.Although the vHS from V 3d states have been implicated in CDW formation,their three-dimensional nature and temperature evolution remain poorly understood.In this study,we used high-resolution angle-resolved photoemission spectroscopy and density functional theory to reveal pronounced out-of-plane dispersion of vHS and their temperature dependence in KV_(3)Sb_(5).The identified c-axis band folding and scattering channels were directly linked to the CDW order.These results demonstrate that the CDW transition in this family involves cooperative coupling between electron correlations and structural modulation along the c axis.This offers new insights into the interplay of topology,correlations,and lattice instabilities in kagome metals.展开更多
Precision time synchronization underpins a wide array of modern technologies,from relativistic geodesy to distributed quantum networks.Quantum two-way time transfer(QTWTT),which harnesses the tight temporal correlatio...Precision time synchronization underpins a wide array of modern technologies,from relativistic geodesy to distributed quantum networks.Quantum two-way time transfer(QTWTT),which harnesses the tight temporal correlations of energy-time entangled photon pairs,has achieved remarkable sub-picosecond stability[1]while offering intrinsic security against timing attacks[2].Yet,the quantum nocloning theorem—prohibiting the amplification of quantum states—imposes a fundamental barrier to extending QTWTT over long distances due to inevitable signal loss in fiber-optic channels[3].In a recent study published in Science China Physics,Mechanics&Astronomy,a cascaded Q-TWTT architecture is presented that bypasses this challenge by using relay stations to generate and distribute entangled photon pairs[4].展开更多
This work investigates quantum speedups for the popular game named Mastermind,in which there are two participants:the codemaker who selects a secret string,and the codebreaker who submits query strings and receives an...This work investigates quantum speedups for the popular game named Mastermind,in which there are two participants:the codemaker who selects a secret string,and the codebreaker who submits query strings and receives answers from the codemaker.The codebreaker's objective is to learn the secret string in as few queries as possible.This work focuses on playing the Mastermind game on quantum computers using different types of codemaker's answers such as black count,l_(p) distance,and separable distance.We show that the codebreaker can learn the secret with certainty by using quantum algorithms which exhibit a sharp reduction in query numbers compared with their classical counterparts.Specifically,our quantum algorithms require O(klog k)black-count queries,O(logk)l_(p)-distance queries,and O(log M)separable-distance queries to learn the secret s∈[k]^(n),respectively,where M is completely determined by k.Thus,the quantum query complexity is independent of the length n of the secret s,as opposed to the query complexity linear in n of classical algorithms.展开更多
Anderson localization describes disorder-induced phase transitions,distinguishing between localized and extended states.In quasiperiodic systems,a third multifractal state emerges,characterized by unique energy and wa...Anderson localization describes disorder-induced phase transitions,distinguishing between localized and extended states.In quasiperiodic systems,a third multifractal state emerges,characterized by unique energy and wave functions.However,the corresponding multifractal-enriched mobility edges and three-state-coexisting quantum phases have yet to be experimentally detected.In this work,we propose exactly solvable one-dimensional quasiperiodic lattice models that simultaneously host three-statecoexisting quantum phases,with their phase boundaries analytically derived via Avilas global theorem.Furthermore,we propose experimental protocols via Rydberg atom arrays to realize these states.Notably,we demonstrate a spectroscopic technique capable of measuring inverse participation ratios across real-space and dual-space domains,enabling simultaneous characterization of localized,extended,and multifractal quantum phases in systems with up to tens of qubits.Our work opens new avenues for the experimental exploration of Anderson localization and multifractal states in artificial quantum systems.展开更多
Entanglement-enhanced quantum sensors encounter a fundamental trade-off:while entanglement improves precision to the Heisenberg limit,it restricts dynamic range.To address this trade-off,we present a credible-interval...Entanglement-enhanced quantum sensors encounter a fundamental trade-off:while entanglement improves precision to the Heisenberg limit,it restricts dynamic range.To address this trade-off,we present a credible-interval-based adaptive Bayesian quantum frequency estimation protocol for Greenberger-Horne-Zeilinger(GHZ)-state-based atomic clocks.Our method optimally integrates prior knowledge with new measurements and determines the interrogation time by correlating it with the period of the likelihood function,based on Bayesian credible intervals.Our protocol can be implemented using either individual or cascaded GHZ states,thereby extending the dynamic range without compromising Heisenberg-limited sensitivity.In parallel with the cascaded-GHZ-state protocol using fixed interrogation times,the dynamic range can be extended through an interferometry sequence that employs individual GHZ states with variable interrogation times.Furthermore,by varying the interrogation times,the dynamic range of the cascaded-GHZ-state protocol can be further extended.Crucially,our protocol enables dual Heisenberglimited precision scaling∝1/Nt in both particle number N and total interrogation time t,surpassing the hybrid scaling∝1/N√t of the conventional cascaded-GHZ-state protocol.While offering a wider dynamic range,the protocol is more stable against noise and more robust to dephasing than existing adaptive schemes.Beyond atomic clocks,our approach establishes a general framework for developing entanglement-enhanced quantum sensors that simultaneously achieve both high precision and broad dynamic range.展开更多
Magneto-optical traps (MOTs) composed of magnetic fields and light fields have been widely utilized to cool andconfine microscopic particles. Practical technology applications require miniaturized MOTs. The advancemen...Magneto-optical traps (MOTs) composed of magnetic fields and light fields have been widely utilized to cool andconfine microscopic particles. Practical technology applications require miniaturized MOTs. The advancement of planaroptics has promoted the development of compact MOTs. In this article, we review the development of compact MOTs basedon planar optics. First, we introduce the standardMOTs. We then introduce the gratingMOTs with micron structures, whichhave been used to build cold atomic clocks, cold atomic interferometers, and ultra-cold sources. Further, we introducethe integrated MOTs based on nano-scale metasurfaces. These new compact MOTs greatly reduce volume and powerconsumption, and provide new opportunities for fundamental research and practical applications.展开更多
基金Project supported by the National Natural Science Foun-dation of China(Grant Nos.62371199 and 62071186)the Natural Science Foundation of Guangdong Province,China(Grant No.2024A1515012427)+1 种基金the Quantum Science Strate-gic Initiative Project of Guangdong Province,China(Grant No.GDZX2305001)the Key Laboratory Project of Guangdong Province,China(Grant No.2020B1212060066).
文摘Weak measurement offers a powerful framework for probing nonclassical features of quantum mechanics,with anomalous weak values serving as operational signatures of contextuality.While the anomalous weak value verification of quantum contextuality has been predominantly investigated in the single-photon regime and analyzed under approximation condition of infinitesimally small perturbation strength.This study releases the approximation condition and takes into account the impact of perturbation strength on the rigor of the verification.And the investigation on the verification of contextuality is extended to the multi-photon scenarios for observing the influence of the correlation between photons on the verification.Without the limitation of infinitesimally small probability of disturbance,anomalous weak values are identified as necessary for contextuality to emerge,thereby refining the criterion proposed by Pusey[Phys.Rev.Lett.113200401(2014)].In the multi-photon scenarios,the emergence of contextuality also depends strongly on both the photon number and the photon-number distribution state.In particular,contextuality is found to be maximized when the single-photon component dominates and the second-order correlation is lower.These results highlight the critical role of photon statistics in experimental tests of contextuality via anomalous weak values.
基金Project supported by the National Natural Science Foundation of China (Grant No.11974156)the Guangdong Innovative and Entrepreneurial Research Team Program (Grant No.2019ZT08C044)+1 种基金the Shenzhen Science and Technology Program (Grant Nos.KQTD20190929173815000 and 20200925161102001)the Science,Technology and Innovation Commission of Shenzhen Municipality (Grant No.ZDSYS20190902092905285)。
文摘Transmission electron microscopy(TEM)offers unparalleled atomic-resolution imaging of complex materials and heterogeneous structures.However,high-energy imaging electrons can induce structural damage,posing a challenge for electron-beam-sensitive materials.Cryogenic TEM(Cryo-TEM)has revolutionized structural biology,enabling the visualization of biomolecules in their near-native states at unprecedented detail.The low electron dose imaging and stable cryogenic environment in Cryo-TEM are now being harnessed for the investigation of electron-beam-sensitive materials and low-temperature quantum phenomena.Here,we present a systematic review of the interaction mechanisms between imaging electrons and atomic structures,illustrating the electron beam-induced damage and the mitigating role of Cryo-TEM.This review then explores the advancements in low-dose Cryo-TEM imaging for elucidating the structures of organic-based materials.Furthermore,we showcase the application of Cryo-TEM in the study of strongly correlated quantum materials,including the detection of charge order and novel topological spin textures.Finally,we discuss the future prospects of Cryo-TEM,emphasizing its transformative potential in unraveling the complexities of materials and phenomena across diverse scientific disciplines.
基金supported by the National Natural Science Foundation of China(Grant Nos.12441502,12122506,12204230,and 12404554)the National Science and Technology Major Project of the Ministry of Science and Technology of China(2024ZD0300404)+6 种基金Guangdong Basic and Applied Basic Research Foundation(Grant No.2021B1515020070)Shenzhen Science and Technology Program(Grant No.RCYX20200714114522109)China Postdoctoral Science Foundation(CPSF)(2024M762114)Postdoctoral Fellowship Program of CPSF(GZC20231727)supported by the National Natural Science Foundation of China(Grant Nos.92165206 and 11974330)Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301603)the Fundamental Research Funds for the Central Universities。
文摘We present a robust quantum optimal control framework for implementing fast entangling gates on ion-trap quantum processors.The framework leverages tailored laser pulses to drive the multiple vibrational sidebands of the ions to create phonon-mediated entangling gates and,unlike the state of the art,requires neither weakcoupling Lamb-Dicke approximation nor perturbation treatment.With the application of gradient-based optimal control,it enables finding amplitude-and phase-modulated laser control protocols that work without the Lamb-Dicke approximation,promising gate speeds on the order of microseconds comparable to the characteristic trap frequencies.Also,robustness requirements on the temperature of the ions and initial optical phase can be conveniently included to pursue high-quality fast gates against experimental imperfections.Our approach represents a step in speeding up quantum gates to achieve larger quantum circuits for quantum computation and simulation,and thus can find applications in near-future experiments.
基金supported by the National Key Research and Development Program of Chinathe National Natural Science Foundation of China (Grant Nos.2024YFA1408000,12474097,and2023YFA1406001)+2 种基金the Guangdong Provincial Quantum Science Strategic Initiative (Grant No.GDZX2201001)the Center for Computational Science and Engineering at Southern University of Science and Technology,the Major Science and Technology Infrastructure Project of Material Genome Big-science Facilities Platform supported by Municipal Development and Reform Commission of Shenzhen(for J.L.Z.and Y.L.)the Chinese funding sources applied via HPSTAR。
文摘The magnetic properties and Kondo effect in Ce_(3)TiBi_(5) with a quasi-one-dimensional structure were investigated using in situ high-pressure resistivity measurements up to 48 GPa.At ambient pressure,Ce_(3)TiBi_(5) undergoes an antiferromagnetic(AFM)transition at T_(N)∼5 K.Under high pressures within 8.9 GPa,we find that Kondo scattering contributes differently to the high-temperature resistance,R(T),depending on the applied current direction,demonstrating a significantly anisotropic Kondo effect.The complete P–T phase diagram has been constructed,in which the pressure dependence of T_(N) exhibits a dome-like shape.The AFM order remains robust under pressure,even when the coherence temperature T^(*) far exceeds 300 K.We attribute the observed anisotropic Kondo effect and the robust AFM to the underlying anisotropy in electronic hybridization under high pressure.
基金supported by the National Natural Science Foundation of China(Grant No.12474159)the Fundamental Research Funds for the Central University,Sun Yat-sen University(Grant No.24qnpy119)the China Postdoctoral Science Foundation(Grant No.2024T171067)。
文摘We investigate distinct non-Hermitian skin effects(NHSEs)in real and Fock spaces induced by the interplay between the Hilbert space fragmentation and multiple non-Hermitian pumping channels.Using an extended Hatano–Nelson model with next-nearest neighbor hopping and strong interaction as an example,we found that two fermions loaded in the lattice exhibit different real-space NHSE depending on the Hilbert space fragments to which they belong.Moreover,in the high-energy sector resulting from fragmentation,the two-particle-bound states form a one-dimensional lattice in Fock space,producing a Fock-space NHSE.At half-filling,richer patterns of Fock-space skin-like localization emerge for the different fragmented energy sectors and subsectors while realspace NHSE is suppressed by many-body effects.This study extends our understanding of the interplay between NHSE and Hilbert space fragmentation and provides detailed insights into their manifestation in interacting non-Hermitian systems.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB4600158)。
文摘We report on a Kerr-lens mode-locked(KLM)femtosecond Yb:CaYAlO_(4)(Yb:CYA)laser operating at a repetition rate of 1.04 GHz,pumped by a single-mode fiber laser.The laser delivers an average output power of 1.37 W with a pulse duration of 109 fs.Potential improvements,including scaling the pump power,increasing the repetition rate,and further reducing the pulse duration,are discussed.This study contributes to the advancement of Watt-level GHz femtosecond laser generation and its applications.
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1407100 and 2020YFA0710100)the National Natural Science Foundation of China(Grant Nos.12374410 and 12361161667)。
文摘The introduction of machine learning algorithms has revolutionized the design of invisible devices,particularly in the intricate domain of elasto-dynamics.In this study,we proposed a core-shell configuration to realize elastic sphere cloaks driven by a Bayesian optimization algorithm to pinpoint the optimal configuration with high precision.Numerical simulations in solid and aqueous environments were performed to validate the cloaking efficacy of our design and the parameters identified by the algorithm.The results closely agreed with the theoretical predictions,underscoring the robustness of the proposed method.This approach provides new insights into the design of elastic wave invisibility devices and has potential applications in underwater communication and sonar detection.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12461160274 and 12004104)Shenzhen Fundamental Research Program (Grant No. JCYJ20230807093301003)+1 种基金the Major Science and Technology Infrastructure Project of Material Genome Big-science Facilities Platform supported by Municipal Development and Reform Commission of Shenzhensupported by Guangdong Provincial Quantum Science Strategic Initiative (Grant No. GDZX2201001)。
文摘This study systematically investigates the transport and point-contact Andreev reflection spectroscopy(PCARS) properties of Bi-doped BaFe_(2)(As_(1-x)Bi_(x))_(2) crystals under high pressures up to 8.7 GPa. The superconducting critical temperature(T_(c)) and upper critical field(H_(c2)) initially decrease with pressure but exhibit a local maximum around 2.9 GPa before further suppression, which can be related to the superconducting transition in the parent compound. The conductance spectrum is consistent with a two-band s-wave model, confirming multi-band superconductivity. The superconducting energy gaps and coupling strengths decrease monotonically with pressure, with the larger gap transitioning from strong to weak coupling. These results provide insight into the interplay between structural, electronic, and superconducting properties in isovalent-doped 122 Fe-based superconductors.
基金Project supported by the National Key Research&Development Program of China(Grant Nos.2019YFA0308600 and 2020YFA0309000)the National Natural Science Foundation of China(Grant Nos.92365302,92065201,22325203,92265105,12074247,12174252,52102336)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)the Science and Technology Commission of Shanghai Municipality(Grant Nos.2019SHZDZX01,19JC1412701,20QA1405100,24LZ1401000,LZPY2024-04)financial support from the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302500)。
文摘Manipulating and braiding Majorana zero modes(MZM)are a critical step toward realizing topological quantum computing.The primary challenge is controlling the vortex,which hosts the MZM,within a superconducting film in a spatially precise manner.To address this,we developed a magnetic force-based vortex control technology using the STM system with a self-designed four-electrode piezo-scanner tube and investigated vortex manipulation on the NbSe_(2) superconducting film.We employed ferromagnetic tips to control the movement of vortex array induced by the tip's remanent magnetism.A magnetic core solenoid device was integrated into the STM system and a strong magnetic tip demagnetization technique was developed,providing a viable technical solution for further enabling single vortex manipulation.
基金supported by the Science and Technology Plan Project of Tangshan Science and Technology Bureau(No.22130217H)the Natural Science Foundation-Steel and Iron Foundation of Hebei Province(No.E2022209114)the Open Research Fund from Guangxi Key Laboratory of Information Materials,Guilin University of Electronic Technology(No.221004-K).
文摘Two-dimensional(2D)MoO_(2),a binary nonlayered material,has been extensively studied for potential applications in catalysis and electronics.However,the preparation of 2D MoO_(2) remains challenging.Herein,we report the growth of 2D MoO_(2) flakes with rhombic morphology on the sapphire substrate via a chemical vapor deposition(CVD)method.Atomic force microscopy shows the CVDgrown MoO_(2) flakes with thin thickness.The CVD-obtained MoO_(2) with a stoichiometric ratio of 1:2 is verified using energy-dispersive X-ray spectroscopy.Scanning transmission electron microscopy(STEM)characterization reveals the high-quality,single-crystal nature of the CVDderived 2D MoO_(2) flakes.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1403102)the National Natural Science Foundation of China(Grant Nos.12474478,92065102,and 61804056).
文摘The intrinsic antiferromagnetic topological insulators in the Mn-Bi-Te family,composed of superlattice-like MnBi_(2)Te_(4)/(Bi_(2)Te_(3))_(n)(n=0,1,2,3,...)layered structure,present intriguing states of matter such as quantum anomalous Hall effect and the axion insulator.However,the surface state gap,which is the prerequisite for the observation of these states,remains elusive.Here by molecular beam epitaxy,we obtain two types of MnBi_(4)Te_(7)films with the exclusive Bi_(2)Te_(3)(BT)or MnBi_(2)Te_(4)(MBT)terminations.By scanning tunneling spectroscopy,the mass terms in the surface states are identified on both surface terminations.Experimental results reveal the existence of a hybridization gap of approximately 23 meV in surface states on the BT termination.This gap comes from the hybridization between the surface states and the spin-split states in the adjacent MBT layer.On the MBT termination,an exchange mass term of about 28±2 meV in surface states is identified by taking magnetic-field-dependent Landau level spectra as well as theoretical simulations.In addition,the mass term varies with the field in the film with a heavy BiMn doping level in the Mn layers.These findings demonstrate the existence of mass terms in surface states on both types of terminations in our epitaxial MnBi_(4)Te_(7)films investigated by local probes.
基金supported by the National Natural Science Foundation of China(Grant Nos.12488201 and 12404215)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302403)+1 种基金Guangdong Provincial Quantum Science Strategic Initiative(Grant Nos.GDZX2401001 and GDZX2401009)supported by the U.S.Department of Energy,Basic Energy Sciences(Grant No.DE-FG02-99ER45747)。
文摘In unconventional high-temperature(high-T_(c))superconductors,the pair density wave state,an exotic superconducting order showing spatially periodic order parameter modulations with the period of several unit cells and translational symmetry breaking,has attracted broad attention.However,the superconducting pair density modulation(PDM)within a single unit cell has never been carefully investigated before.Here,using scanning tunneling microscopy/spectroscopy,we report the observation of PDM in monolayer high-T_(c) iron chalcogenide films epitaxially grown on SrTiO_(3)(001).The superconductivity modulations are characterized by the superconducting gap size and the coherence peak sharpness.Further analysis shows that the local maxima and minima in the superconducting gap modulation are centered at the crystallographic locations of the chalcogen atoms,revealing the breaking of the glide-mirror symmetry of the chalcogen atoms in monolayer high-T_(c) iron chalcogenide films grown on SrTiO_(3)(001).Our findings provide precise microscopic information on superconductivity within the lattice unit cell and may promote the understanding of unconventional high-T_(c) superconductivity.
基金supported by Shanghai Tech University and Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area,China(Grant No.SZZX2301006)。
文摘Over the past few decades,angle-resolved photoemission spectroscopy(ARPES)has been one of the important tools to study electronic structure of crystals.In recent years,the spatial resolution of around 150 nm has been reached through tight focusing of the light spot(nano-ARPES).At present,the lower limit of the spot size of the light on the sample has been reached.Another way to further improve the spatial resolution is through using apertures to only let electrons from a small area of the sample pass.With both back-focal plane and image apertures,the size of the selected area can be as small as 20 nm.Yet,without aberration correction,the maximum opening angle at the sample for 20 nm spatial resolution is usually smaller than 3°,making this method not suitable for nano-ARPES.As shown in this paper,a conventional aberration corrector,which corrects chromatic and third-order spherical aberrations,is not enough either.Only when the fifth-order spherical aberration is also corrected,the opening angle at the sample is large enough for nano-ARPES.In this paper,the design of a time-of-fight PEEM/ARPES/nano-ARPES instrument,which is currently under development at the Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area,is presented.The main point of innovation is a fiveelectrode electron mirror corrector,which is used to correct simultaneously chromatic,third-order and fifth-order spherical aberrations,resulting in 1 nm spatial resolution with~230 mrad aperture angle in PEEM mode.This makes feasible the method of using apertures to improve the spatial resolution of the nano-ARPES mode.A new design of the magnetic prism array(MPA)is also presented,which preserves the rotational symmetry better than the existing designs.
基金supported by the National Natural Science Foundation of China(Grant Nos.92365302,92065201,12488101,22325203,92265105,12074247,12174252,and 52102336)the Ministry of Science and Technology of China(Grant Nos.2019YFA0308600 and 2020YFA0309000)+1 种基金the Science and Technology Commission of Shanghai Municipality(Grant Nos.2019SHZDZX01,19JC1412701,20QA1405100,24LZ1401000,and LZPY2024-04)the financial support from Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302500)。
文摘Topological superconductor islands are thought to be the building blocks of topological quantum bits.We produced single-crystalline VSi_(x)islands with well-defined side facets and island size more than 200nm using molecular beam epitaxy on Si substrate heated to 950℃throughout the growth process.By means of scanning tunneling spectroscopy,we revealed dynamical Coulomb blockade and superconductivity on isolated islands and on islands being connected by superconducting wetting layer respectively.Bi_(2)Te_(3)films were further deposited on VSi_(x)islands.Robust and homogenous proximity effect induced superconductivity was observed on various facets of the Bi_(2)Te_(3)/VSi_(x)hetero-nanostructure.Furthermore,our high-resolution spectroscopy identified Bosonic mode excitations on the topological superconductor islands.These results may establish a playground for the vortex Majorana islands.
基金supported by the National Key R&D Program of China(Grant Nos.2023YFA1406304 and 2024YFA1408103)the National Science Foundation of China(Grant Nos.12494593 and 12004405)+5 种基金the Anhui Provincial Natural Science Foundation(Grant No.2408085J003)the National Key R&D Program of China(Grant No.2023YFA1406100)the open projects of the State Key Laboratory of Functional Materials for Informatics(Grant No.SKL2022)the China National Postdoctoral Program for Innovative Talents(BX20240348)support from the National Natural Science Foundation of China(Grant No.12404186)the Shanghai Sailing Program(Grant No.23YF1426900)。
文摘The kagome metals AV_(3)Sb_(5)(A=K,Rb,Cs)feature intertwined Dirac fermions,topological flat bands,and van Hove singularities(vHS)near the Fermi level,which give rise to a range of exotic,strongly correlated phenomena such as charge density waves(CDW)and superconductivity.Although the vHS from V 3d states have been implicated in CDW formation,their three-dimensional nature and temperature evolution remain poorly understood.In this study,we used high-resolution angle-resolved photoemission spectroscopy and density functional theory to reveal pronounced out-of-plane dispersion of vHS and their temperature dependence in KV_(3)Sb_(5).The identified c-axis band folding and scattering channels were directly linked to the CDW order.These results demonstrate that the CDW transition in this family involves cooperative coupling between electron correlations and structural modulation along the c axis.This offers new insights into the interplay of topology,correlations,and lattice instabilities in kagome metals.
文摘Precision time synchronization underpins a wide array of modern technologies,from relativistic geodesy to distributed quantum networks.Quantum two-way time transfer(QTWTT),which harnesses the tight temporal correlations of energy-time entangled photon pairs,has achieved remarkable sub-picosecond stability[1]while offering intrinsic security against timing attacks[2].Yet,the quantum nocloning theorem—prohibiting the amplification of quantum states—imposes a fundamental barrier to extending QTWTT over long distances due to inevitable signal loss in fiber-optic channels[3].In a recent study published in Science China Physics,Mechanics&Astronomy,a cascaded Q-TWTT architecture is presented that bypasses this challenge by using relay stations to generate and distribute entangled photon pairs[4].
基金supported by the National Key Research and Development Program of China(Grant No.2024YFB4504004)the National Natural Science Foundation of China(Grant Nos.92465202,62272492,and 12447107)+1 种基金the Guangdong Provincial Quantum Science Strategic Initiative(Grant Nos.GDZX2303007,and GDZX2403001)the Guangzhou Science and Technology Program(Grant No.2024A04J4892)。
文摘This work investigates quantum speedups for the popular game named Mastermind,in which there are two participants:the codemaker who selects a secret string,and the codebreaker who submits query strings and receives answers from the codemaker.The codebreaker's objective is to learn the secret string in as few queries as possible.This work focuses on playing the Mastermind game on quantum computers using different types of codemaker's answers such as black count,l_(p) distance,and separable distance.We show that the codebreaker can learn the secret with certainty by using quantum algorithms which exhibit a sharp reduction in query numbers compared with their classical counterparts.Specifically,our quantum algorithms require O(klog k)black-count queries,O(logk)l_(p)-distance queries,and O(log M)separable-distance queries to learn the secret s∈[k]^(n),respectively,where M is completely determined by k.Thus,the quantum query complexity is independent of the length n of the secret s,as opposed to the query complexity linear in n of classical algorithms.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1405300)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301700)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2021A1515012350)the Guangdong Provincial Quantum Science Strategic Initiative(Grant Nos.GDZX2304002 and GDZX2404001)the Open Fund of Key Laboratory of Atomic and Subatomic Structure and Quantum Control(Ministry of Education)。
文摘Anderson localization describes disorder-induced phase transitions,distinguishing between localized and extended states.In quasiperiodic systems,a third multifractal state emerges,characterized by unique energy and wave functions.However,the corresponding multifractal-enriched mobility edges and three-state-coexisting quantum phases have yet to be experimentally detected.In this work,we propose exactly solvable one-dimensional quasiperiodic lattice models that simultaneously host three-statecoexisting quantum phases,with their phase boundaries analytically derived via Avilas global theorem.Furthermore,we propose experimental protocols via Rydberg atom arrays to realize these states.Notably,we demonstrate a spectroscopic technique capable of measuring inverse participation ratios across real-space and dual-space domains,enabling simultaneous characterization of localized,extended,and multifractal quantum phases in systems with up to tens of qubits.Our work opens new avenues for the experimental exploration of Anderson localization and multifractal states in artificial quantum systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.12025509,12104521,12475029,and 92476201)the National Key Research and Development Program of China(Grant No.2022YFA1404104)the Guangdong Provincial Quantum Science Strategic Initiative(Grant Nos.GDZX2305006,and GDZX2405002)。
文摘Entanglement-enhanced quantum sensors encounter a fundamental trade-off:while entanglement improves precision to the Heisenberg limit,it restricts dynamic range.To address this trade-off,we present a credible-interval-based adaptive Bayesian quantum frequency estimation protocol for Greenberger-Horne-Zeilinger(GHZ)-state-based atomic clocks.Our method optimally integrates prior knowledge with new measurements and determines the interrogation time by correlating it with the period of the likelihood function,based on Bayesian credible intervals.Our protocol can be implemented using either individual or cascaded GHZ states,thereby extending the dynamic range without compromising Heisenberg-limited sensitivity.In parallel with the cascaded-GHZ-state protocol using fixed interrogation times,the dynamic range can be extended through an interferometry sequence that employs individual GHZ states with variable interrogation times.Furthermore,by varying the interrogation times,the dynamic range of the cascaded-GHZ-state protocol can be further extended.Crucially,our protocol enables dual Heisenberglimited precision scaling∝1/Nt in both particle number N and total interrogation time t,surpassing the hybrid scaling∝1/N√t of the conventional cascaded-GHZ-state protocol.While offering a wider dynamic range,the protocol is more stable against noise and more robust to dephasing than existing adaptive schemes.Beyond atomic clocks,our approach establishes a general framework for developing entanglement-enhanced quantum sensors that simultaneously achieve both high precision and broad dynamic range.
基金the National Key Research and Development Program of China(Grant No.2022YFA1404104)the National Natural Science Foundation of China(Grant Nos.12025509 and 12104521)Fundamental Research Project of Shenzhen(Grant No.JCYJ20230808105009018).
文摘Magneto-optical traps (MOTs) composed of magnetic fields and light fields have been widely utilized to cool andconfine microscopic particles. Practical technology applications require miniaturized MOTs. The advancement of planaroptics has promoted the development of compact MOTs. In this article, we review the development of compact MOTs basedon planar optics. First, we introduce the standardMOTs. We then introduce the gratingMOTs with micron structures, whichhave been used to build cold atomic clocks, cold atomic interferometers, and ultra-cold sources. Further, we introducethe integrated MOTs based on nano-scale metasurfaces. These new compact MOTs greatly reduce volume and powerconsumption, and provide new opportunities for fundamental research and practical applications.
