There has been immense research interest in quantum entanglement due to its ability to generate stronger-thanclassical nonlocal correlations.^([1,2])These strong,nonlocal correlations form the backbone of various quan...There has been immense research interest in quantum entanglement due to its ability to generate stronger-thanclassical nonlocal correlations.^([1,2])These strong,nonlocal correlations form the backbone of various quantum information protocols.One of the core principles of quantum entanglement is quantum coherence,which provides deep insights into the statistical correlations among quantum particles.^([3–5])Quantum coherence reflects the wavelike properties of quantum particles,enabling them to exhibit interference and unique quantum behaviors.展开更多
Acoustic detection has many applications across science and technology from medicine to imaging and communications.However,most acoustic sensors have a common limitation in that the detection must be near the acoustic...Acoustic detection has many applications across science and technology from medicine to imaging and communications.However,most acoustic sensors have a common limitation in that the detection must be near the acoustic source.Alternatively,laser interferometry with picometer-scale motional displacement detection can rapidly and precisely measure sound-induced minute vibrations on remote surfaces.Here,we demonstrate the feasibility of sound detection up to 100 kHz at remote sites with≈60 m optical path length via laser homodyne interferometry.Based on our ultrastable hertz linewidth laser with 10-15 fractional stability,our laser interferometer achieves 0.5 pm/Hz1/2 displacement sensitivity near 10 kHz,bounded only by laser frequency noise over 10 kHz.Between 140 Hz and 15 kHz,we achieve a homodyne acoustic sensing sensitivity of subnanometer/Pascal across our conversational frequency overtones.The minimal sound pressure detectable over 60 m optical path length is≈2 mPa,with dynamic ranges over 100 dB.With the demonstrated standoff picometric distance metrology,we successfully detected and reconstructed musical scores of normal conversational volumes with high fidelity.The acoustic detection via this precision laser interferometer could be applied to selective area sound sensing for remote acoustic metrology,optomechanical vibrational motion sensing,and ultrasensitive optical microphones at the laser frequency noise limits.展开更多
Laser frequency microcombs provide a series of equidistant,coherent frequency markers across a broad spectrum,enabling advancements in laser spectroscopy,dense optical communications,precision distance metrology,and a...Laser frequency microcombs provide a series of equidistant,coherent frequency markers across a broad spectrum,enabling advancements in laser spectroscopy,dense optical communications,precision distance metrology,and astronomy.Here,we design and fabricate silicon nitride,dispersion-managed microresonators that effectively suppress avoided-mode crossings and achieve close-to-zero averaged dispersion.Both the stochastic noise and mode-locking dynamics of the resonator are numerically and experimentally investigated.First,we experimentally demonstrate thermally stabilized microcomb formation in the microresonator across different mode-locked states,showing negligible center frequency shifts and a broad frequency bandwidth.Next,we characterize the femtosecond timing jitter of the microcombs,supported by precise metrology of the timing phase and relative intensity noise.For the single-soliton state,we report a relative intensity noise of−153.2 dB∕Hz,close to the shot-noise limit,and a quantum-noise–limited timing jitter power spectral density of 0.4 as 2∕Hz at a 100 kHz offset frequency,measured using a self-heterodyne linear interferometer.In addition,we achieve an integrated timing jitter of 1.7 fs±0.07 fs,measured from 10 kHz to 1 MHz.Measuring and understanding these fundamental noise parameters in high clock rate frequency microcombs is critical for advancing soliton physics and enabling new applications in precision metrology.展开更多
The wave-particle duality relation derived by Englert sets an upper bound of the extractable information from wave and particle properties in a two-path interferometer.Surprisingly,previous studies demonstrated that t...The wave-particle duality relation derived by Englert sets an upper bound of the extractable information from wave and particle properties in a two-path interferometer.Surprisingly,previous studies demonstrated that the introduction of a quantum beamsplitter in the interferometer could break the limitation of this upper bound,due to interference between wave and particle states.Along the other line,a lot of efforts have been made to generalize this relation from the two-path setup to the N-path case.Thus,it is an interesting question that whether a quantum N-path beamsplitter can break the limitation as well.This paper systemically studies the model of a quantum N-path beamsplitter,and finds that the generalized wave-particle duality relation between interference visibility and path distinguishability is also broken in certain situations.We further study the maximal extractable information's reliance on the interference between wave and particle properties,and derive a quantitative description.We then propose an experimental methodology to verify the break of the limitation.Our work reflects the effect of quantum superposition on wave-particle duality,and exhibits a new aspect of the relation between visibility and path distinguishability in N-path interference.Moreover,it implies the observer's influence on wave-particle duality.展开更多
Quantum teleportation with entanglement channels and a series of two-qubit SWAP gates between the nearestneighbor qubits are usually utilized to achieve the transfers of unknown quantum state from the sender to the di...Quantum teleportation with entanglement channels and a series of two-qubit SWAP gates between the nearestneighbor qubits are usually utilized to achieve the transfers of unknown quantum state from the sender to the distant receiver. In this paper, by simplifying the usual SWAP gates we propose an approach to speed up the transmissions of unknown quantum information, specifically including the single-qubit unknown state and two-qubit unknown entangled ones,by a series of entangling and disentangling operations between the remote qubits with distant interactions. The generic proposal is demonstrated specifically with experimentally-existing Ising-type quantum channels without transverse interaction; liquid NMR-molecules driven by global radio frequency electromagnetic pulses and capacitively-coupled Josephson circuits driven by local microwave pulses. The proposal should be particularly useful to set up the connections between the distant qubits in a chip of quantum computing.展开更多
Stark-chirped rapid adiabatic passage(SCRAP) is an important technique used for coherent quantum controls. In this paper we investigate how the practically-existing dissipation of the system influences on the efficien...Stark-chirped rapid adiabatic passage(SCRAP) is an important technique used for coherent quantum controls. In this paper we investigate how the practically-existing dissipation of the system influences on the efficiency of the passage, and thus the fidelities of the SCRAP-based quantum gates. With flux-biased Josephson qubits as a specifical example, our results show clearly that the efficiency of the logic gates implemented by SCRAP are robust against the weak dissipation. The influence due to the non-adiabtic transitions between the adiabatic passages is comparatively significantly small. Therefore, the SCRAP-based logic gates should be feasible for the realistic physical systems with noises.展开更多
An approach is proposed to implement the universal quantum gates between the ions confined individually in the separated traps.Instead of the typical adiabatic operations,performed for manipulating the ion-ion couplin...An approach is proposed to implement the universal quantum gates between the ions confined individually in the separated traps.Instead of the typical adiabatic operations,performed for manipulating the ion-ion coupling,here the switchable couplings between ions are implemented non-adiabatically by using the fast laser pulses.Consequently,the desirable quantum gates between the ions could be implemented by using only a series of laser pulses.The proposal may be conveniently generalized to the quantum computation with the scalable ion-traps.展开更多
Very recently,Lee et al.proposed a secure quantum teleportation protocol to transfer shared quantum secret between multiple parties in a network[Phys.Rev.Lett.124060501(2020)].This quantum network is encoded with a ma...Very recently,Lee et al.proposed a secure quantum teleportation protocol to transfer shared quantum secret between multiple parties in a network[Phys.Rev.Lett.124060501(2020)].This quantum network is encoded with a maximally entangled GHZ state.In this paper,we consider a partially entangled GHZ state as the entanglement channel,where it can achieve,probabilistically,unity fidelity transfer of the state.Two kinds of strategies are given.One arises when an auxiliary particle is introduced and a general evolution at any receiver's location is then adopted.The other one involves performing a single generalized Bell-state measurement at the location of any sender.This could allow the receivers to recover the transmitted state with a certain probability,in which only the local Pauli operators are performed,instead of introducing an auxiliary particle.In addition,the successful probability is provided,which is determined by the degree of entanglement of the partially multipartite entangled state.Moreover,the proposed protocol is robust against the bit and phase flip noise.展开更多
The synthetic Floquet lattice,generated by multiple strong drives with mutually incommensurate frequencies,provides a powerful platform for quantum simulation of topological phenomena.In this study,we propose a 4-band...The synthetic Floquet lattice,generated by multiple strong drives with mutually incommensurate frequencies,provides a powerful platform for quantum simulation of topological phenomena.In this study,we propose a 4-band tight-binding model of the Chern insulator with a Chern number C=±2 by coupling two layers of the half Bernevig–Hughes–Zhang lattice and subsequently mapping it onto the Floquet lattice to simulate its topological properties.To determine the Chern number of our Floquet-version model,we extend the energy pumping method proposed by Martin et al.[2017 Phys.Rev.X 7041008]and the topological oscillation method introduced by Boyers et al.[2020 Phys.Rev.Lett.125160505],followed by numerical simulations for both methodologies.The simulation results demonstrate the successful extraction of the Chern number using either of these methods,providing an excellent prediction of the phase diagram that closely aligns with the theoretical one derived from the original bilayer half Bernevig–Hughes–Zhang model.Finally,we briefly discuss a potential experimental implementation for our model.Our work demonstrates significant potential for simulating complex topological matter using quantum computing platforms,thereby paving the way for constructing a more universal simulator for non-interacting topological quantum states and advancing our understanding of these intriguing phenomena.展开更多
A pioneering chip-based quantum digital signature(QDS)network achieves secure document signing over 200 km of fiber,leveraging integrated photonics to miniaturize transmitters and centralize measurement systems.This b...A pioneering chip-based quantum digital signature(QDS)network achieves secure document signing over 200 km of fiber,leveraging integrated photonics to miniaturize transmitters and centralize measurement systems.This breakthrough paves the way for future scalable,cost-effective,and robust quantum-secure communication networks.展开更多
In this work,calcium niobium gallium garnet(Ca_(3)Nb_(1.6875)Ga_(3.1875)O_(12)-CNGG)ceramic samples singledoped with Tb^(3+)and co-doped with Tb^(3+)and Yb^(3+)ions were sintered by the solid-state reaction method.The...In this work,calcium niobium gallium garnet(Ca_(3)Nb_(1.6875)Ga_(3.1875)O_(12)-CNGG)ceramic samples singledoped with Tb^(3+)and co-doped with Tb^(3+)and Yb^(3+)ions were sintered by the solid-state reaction method.The structural characterization of the samples was carried out by X-ray diffraction measurements.The optimal concentration of Tb^(3+)ions corresponding to the maximum luminescence in the green spectral range in CNGG:x at%Tb(x=0.1,0.5,1,2,3,4,and 5)was determined to be 4 at%.The timeresolved luminescence of the^(5)D_(4)level(Tb^(3+))in the CNGG:x at%Tb samples was analysed to explore the quenching mechanisms involved in the Tb^(3+)green emission.Co-doped CNGG:4 at%Tb,y at%Yb(y=0.5,2,4,6,8,and 10)ceramics were prepared and investigated.It is shown that CNGG:4 at%Tb,y at%Yb phosphors exhibit intense green luminescence under ultra-violet(UV),visible(VIS),and near-infrared(NIR)excitation,thus demonstrating the presence of simultaneous down-conversion(DC)and upconversion(UC)processes.The dependence of the UC luminescence intensity on the diode laser pumping power was measured and the results indicate a two-photon process based on cooperative energy transfer(CET).Under UV excitation,the lifetime of the^(5)D_(4)(Tb^(3+))level slowly increases with increase of Yb^(3+)concentration,suggesting the energy transfer from Yb^(3+)to Tb^(3+)ions,while under NIR excitation,the lifetime of the^(5)D_(4)(Tb^(3+))level decreases with increase of Yb^(3+)ions concentration,indicating the presence of a strong energy transfer from Tb^(3+)to Yb^(3+)ions.The highest energy transfer efficiency ofη_(ET)≈42%was determined for the CNGG:4 at%Tb,10 at%Yb sample.The obtained results indicate that CNGG:(Tb^(3+),Yb^(3+))could be efficient new yellowish-green-emitting phosphors.展开更多
We experimentally demonstrate perfect discrimination between two unitary operations by using the sequential scheme proposed by Duan et al.[Phys. Rev. Lett. 98 （2007） 100503] Also, we show how to understand the schem...We experimentally demonstrate perfect discrimination between two unitary operations by using the sequential scheme proposed by Duan et al.[Phys. Rev. Lett. 98 （2007） 100503] Also, we show how to understand the scheme and to calculate the parameters for two-dimensional operations in the picture of the Bloch sphere.展开更多
Nonsequential double ionization （NSDI） processes of nonaligned diatomic molecules N2 and O2 are studied using the S-matrix theory. Our results show that the NSDI process significantly depends on the molecular symmet...Nonsequential double ionization （NSDI） processes of nonaligned diatomic molecules N2 and O2 are studied using the S-matrix theory. Our results show that the NSDI process significantly depends on the molecular symmetry and structure. The ratio of NSDI rate to single ionization rate as a function of the field intensity is obtained. It is found that N2 behaves closely with its companion atom Ar in the ratios over the entire intensity range, while O2 exhibits an obvious suppression effect, which is qualitatively consistent with the experiment.展开更多
Metasurface is a kind of two-dimensional metamaterial with specially designed sub-wavelength unit cells.It consists of single-layer or few-layer stacks of planar structures and possesses certain superior abilities to ...Metasurface is a kind of two-dimensional metamaterial with specially designed sub-wavelength unit cells.It consists of single-layer or few-layer stacks of planar structures and possesses certain superior abilities to manipulate the propagating electromagnetic waves,including the terahertz(THz)ones.Compared with the usual passive THz metasurfaces whose optical properties are difficult to be controlled after fabrication,the active materials are highly desirable to enable dynamic and tunable control of THz waves.In this review,we briefly summarize the progress of active THz metasurfaces,from their physical mechanisms on carrier concentration modulations,phase transitions,magneto-optical effects,etc.,for various possible THz applications mainly with low-dimensional materials,vanadium dioxide films,and superconductors.展开更多
Hardy＇s theorem on nonlocality has been verified by a series of experiments with two-qubit entangled pure states.However,in this paper we demonstrate the experimental test of the theorem by using the two-photon entan...Hardy＇s theorem on nonlocality has been verified by a series of experiments with two-qubit entangled pure states.However,in this paper we demonstrate the experimental test of the theorem by using the two-photon entangled mixed states.We first investigate the generic logic in Hardy＇s proof of nonlocality,which can be applied for arbitrary two-qubit mixed polarization entangled states and can be reduced naturally to the well-known logic tested successfully by the previous pure state experiments.Then,the optimized violations of locality for various experimental parameters are delivered by the numerical method.Finally,the logic argued above for testing Hardy＇s theorem on nonlocality is demonstrated experimentally by using the mixed entangled-photon pairs generated via pumping two type-I BBO crystals.Our experimental results shows that Hardy＇s proof of nonlocality can also be verified with two-qubit polarization entangled mixed states,with a violation of about 3.4 standard deviations.展开更多
The system of electrons on liquid helium is an interesting candidate to implement quantum computation, due to the long coherence times of the qubits encoded by the electronic spins. In order to implement the quantum l...The system of electrons on liquid helium is an interesting candidate to implement quantum computation, due to the long coherence times of the qubits encoded by the electronic spins. In order to implement the quantum logic operations between the spins, we propose here a configuration, similarly to the cooled ions in a trap, to couple the distant electrons via manipulating their center of mass （CM） vibrations. First, we show that the electrons could be confined in a common harmonic oscillator potential by using an electrostatic field. Then, with a single current pulse （applied on the micro-electrode below the liquid helium） the distant electronic spins can be coupled simultaneously to the CM mode. Finally, by adiabatically eliminating the CM mode, effective interaction between the distant spins is induced for implementing the desired quantum computing.展开更多
A cold atomic medium(Rydberg medium) with cascade configuration under the blockade mechanism is considered. A partial coherent light(PCL) beam is incident on the medium, which makes an angle θ with z-axis. We study t...A cold atomic medium(Rydberg medium) with cascade configuration under the blockade mechanism is considered. A partial coherent light(PCL) beam is incident on the medium, which makes an angle θ with z-axis. We study the influence of PCL field on the transmission spectrum and find high transmission of probe field for PCL field.Conversely, it is investigated that the transparency of probe field decrease for coherent light field. The transmission of probe field is also studied via beam width of PCL field and investigated high transmission of probe field for small beam width and vice versa. Interestingly, the Goos-H?nchen shift(GHS) in the transmitted light(TL) is studied for PCL field. Large negative and positive GHS in the TL are investigated for PCL field and small beam width of PCL field.展开更多
Recently, individual reduced-symmetry metal nanostructures and their plasmonic properties have been studied extensively. However, little attention has been paid to the approach to fabricating ordered reduced-symmetry ...Recently, individual reduced-symmetry metal nanostructures and their plasmonic properties have been studied extensively. However, little attention has been paid to the approach to fabricating ordered reduced-symmetry metal nanostructure arrays. In this paper, a novel perforated silver nanocap array with high surface-enhanced Raman scattering （SERS） activity and fluorescence suppression is reported. The array is fabricated by electron beam evaporating Ag onto the perforated barrier layer side of a hard anodization （HA） anodic aluminum oxide （AAO） template. The morphology and optical property of the perforated silver nanocap array are characterized by an atomic force microscope （AFM）, a scanning electron microscope （SEM）, and absorption spectra. The results of SERS measurements reveal that the perforated silver nanocap array offers high SERS activity and fluorescence suppression compared with an imperforated silver nanocap array.展开更多
We investigate the self-trapping of a Bose Josephson junction, which is dispersively coupled to a driven optical cavity. The cavity-induced nonlinearity is presented analytically, and its effect results in the appeara...We investigate the self-trapping of a Bose Josephson junction, which is dispersively coupled to a driven optical cavity. The cavity-induced nonlinearity is presented analytically, and its effect results in the appearance of the self-trapping for the Bose-Einstein condensates in the Josephson oscillation regime. In addition, there exists competition between the nonlinearities induced by the interatomic interaction and by the driven cavity for the emergences of self-trapping. Our results show that the driven cavity can be utilized as a possible tool to produce the self-trapping for the condensates with weak interatomic interaction.展开更多
<span style="white-space:normal;">The study of high dielectric materials has received great attention lately as a key passive component for the application of metal-insulator-metal (MIM) capacitors. In...<span style="white-space:normal;">The study of high dielectric materials has received great attention lately as a key passive component for the application of metal-insulator-metal (MIM) capacitors. In this paper, 50 nm thick Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;"> thin films have been prepared by atomic layer deposition technique on indium tin oxide (ITO) pre-coated glass substrates and titanium nitride (TiN) coated Si substrates with typical MIM capacitor structure. Photolithography and metal lift-off technique were used for processing of the MIM capacitors. Semiconductor Analyzer with probe station was used to perform capacitance-voltage (C-V) characterization with low-medium frequency range. Current-voltage (I-V) characteristics of MIM capacitors were measured on precision source/measurement system. The performance of Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;"> films of MIM capacitors on glass was examined in the voltage range from <span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span>5 to 5 V with a frequency range from 10 kHz to 5 MHz. Au/Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;">/ITO/Glass MIM capacitors demonstrate a capacitance density of 1.6 fF/μm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;">at 100 kHz, a loss tangent ~0.005 at 100 kHz and a leakage current of 1.79 × 10</span><sup style="white-space:normal;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span>8</sup><span style="white-space:normal;"> A/cm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;"> at 1 MV/cm (5 V) at room temperature. Au/Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;">/TiN/Si MIM capacitors demonstrate a capacitance density of 1.5 fF/μm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;"> at 100 kHz, a loss tangent ~0.007 at 100 kHz and a lower leakage current of 2.93 × 10</span><sup style="white-space:normal;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span>10</sup><span style="white-space:normal;"> A/cm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;"> at 1 MV/cm (5 V) at room temperature. The obtained electrical properties could indicate a promising application of MIM Capacitors.</span>展开更多
文摘There has been immense research interest in quantum entanglement due to its ability to generate stronger-thanclassical nonlocal correlations.^([1,2])These strong,nonlocal correlations form the backbone of various quantum information protocols.One of the core principles of quantum entanglement is quantum coherence,which provides deep insights into the statistical correlations among quantum particles.^([3–5])Quantum coherence reflects the wavelike properties of quantum particles,enabling them to exhibit interference and unique quantum behaviors.
基金supported by the Office of Naval Research(Grant Nos.N00014-16-1-2094 and N00014-24-1-2547)the Lawrence Livermore National Laboratory(Grant No.B622827)the National Science Foundation.Y.-S.J.acknowledges support from KRISS(Grant Nos.25011026 and 25011211).
文摘Acoustic detection has many applications across science and technology from medicine to imaging and communications.However,most acoustic sensors have a common limitation in that the detection must be near the acoustic source.Alternatively,laser interferometry with picometer-scale motional displacement detection can rapidly and precisely measure sound-induced minute vibrations on remote surfaces.Here,we demonstrate the feasibility of sound detection up to 100 kHz at remote sites with≈60 m optical path length via laser homodyne interferometry.Based on our ultrastable hertz linewidth laser with 10-15 fractional stability,our laser interferometer achieves 0.5 pm/Hz1/2 displacement sensitivity near 10 kHz,bounded only by laser frequency noise over 10 kHz.Between 140 Hz and 15 kHz,we achieve a homodyne acoustic sensing sensitivity of subnanometer/Pascal across our conversational frequency overtones.The minimal sound pressure detectable over 60 m optical path length is≈2 mPa,with dynamic ranges over 100 dB.With the demonstrated standoff picometric distance metrology,we successfully detected and reconstructed musical scores of normal conversational volumes with high fidelity.The acoustic detection via this precision laser interferometer could be applied to selective area sound sensing for remote acoustic metrology,optomechanical vibrational motion sensing,and ultrasensitive optical microphones at the laser frequency noise limits.
基金support from the Lawrence Livermore National Laboratory(Grant No.B622827)the National Science Foundation(Grant Nos.1824568,1810506,1741707,and 1829071)the Office of Naval Research(Grant No.N00014-16-1-2094).
文摘Laser frequency microcombs provide a series of equidistant,coherent frequency markers across a broad spectrum,enabling advancements in laser spectroscopy,dense optical communications,precision distance metrology,and astronomy.Here,we design and fabricate silicon nitride,dispersion-managed microresonators that effectively suppress avoided-mode crossings and achieve close-to-zero averaged dispersion.Both the stochastic noise and mode-locking dynamics of the resonator are numerically and experimentally investigated.First,we experimentally demonstrate thermally stabilized microcomb formation in the microresonator across different mode-locked states,showing negligible center frequency shifts and a broad frequency bandwidth.Next,we characterize the femtosecond timing jitter of the microcombs,supported by precise metrology of the timing phase and relative intensity noise.For the single-soliton state,we report a relative intensity noise of−153.2 dB∕Hz,close to the shot-noise limit,and a quantum-noise–limited timing jitter power spectral density of 0.4 as 2∕Hz at a 100 kHz offset frequency,measured using a self-heterodyne linear interferometer.In addition,we achieve an integrated timing jitter of 1.7 fs±0.07 fs,measured from 10 kHz to 1 MHz.Measuring and understanding these fundamental noise parameters in high clock rate frequency microcombs is critical for advancing soliton physics and enabling new applications in precision metrology.
基金the National Natural Science Foundation of China(Grant No.61632021).
文摘The wave-particle duality relation derived by Englert sets an upper bound of the extractable information from wave and particle properties in a two-path interferometer.Surprisingly,previous studies demonstrated that the introduction of a quantum beamsplitter in the interferometer could break the limitation of this upper bound,due to interference between wave and particle states.Along the other line,a lot of efforts have been made to generalize this relation from the two-path setup to the N-path case.Thus,it is an interesting question that whether a quantum N-path beamsplitter can break the limitation as well.This paper systemically studies the model of a quantum N-path beamsplitter,and finds that the generalized wave-particle duality relation between interference visibility and path distinguishability is also broken in certain situations.We further study the maximal extractable information's reliance on the interference between wave and particle properties,and derive a quantitative description.We then propose an experimental methodology to verify the break of the limitation.Our work reflects the effect of quantum superposition on wave-particle duality,and exhibits a new aspect of the relation between visibility and path distinguishability in N-path interference.Moreover,it implies the observer's influence on wave-particle duality.
基金partly supported by the National Natural Science Foundation of China(Grant No.U1330201)
文摘Quantum teleportation with entanglement channels and a series of two-qubit SWAP gates between the nearestneighbor qubits are usually utilized to achieve the transfers of unknown quantum state from the sender to the distant receiver. In this paper, by simplifying the usual SWAP gates we propose an approach to speed up the transmissions of unknown quantum information, specifically including the single-qubit unknown state and two-qubit unknown entangled ones,by a series of entangling and disentangling operations between the remote qubits with distant interactions. The generic proposal is demonstrated specifically with experimentally-existing Ising-type quantum channels without transverse interaction; liquid NMR-molecules driven by global radio frequency electromagnetic pulses and capacitively-coupled Josephson circuits driven by local microwave pulses. The proposal should be particularly useful to set up the connections between the distant qubits in a chip of quantum computing.
基金Supported by the National Science Foundation under Grant Nos.90921010,11174373the National Fundamental Research Program of China under Grant No.2010CB923104+2 种基金National Research Foundation and Ministry of Education,Singapore under Grant No.WBS:R-710-000-008-271the 2013 Doctoral Innovation funds of Southwest Jiaotong Universitythe Fundamental Research Funds for the Central Universities
文摘Stark-chirped rapid adiabatic passage(SCRAP) is an important technique used for coherent quantum controls. In this paper we investigate how the practically-existing dissipation of the system influences on the efficiency of the passage, and thus the fidelities of the SCRAP-based quantum gates. With flux-biased Josephson qubits as a specifical example, our results show clearly that the efficiency of the logic gates implemented by SCRAP are robust against the weak dissipation. The influence due to the non-adiabtic transitions between the adiabatic passages is comparatively significantly small. Therefore, the SCRAP-based logic gates should be feasible for the realistic physical systems with noises.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11147116,10874142 and 90921010the National Basic Research Program of China under Grant No 2010CB923104the Open Project of State Key Laboratory of Functional Materials for Informatics.
文摘An approach is proposed to implement the universal quantum gates between the ions confined individually in the separated traps.Instead of the typical adiabatic operations,performed for manipulating the ion-ion coupling,here the switchable couplings between ions are implemented non-adiabatically by using the fast laser pulses.Consequently,the desirable quantum gates between the ions could be implemented by using only a series of laser pulses.The proposal may be conveniently generalized to the quantum computation with the scalable ion-traps.
基金Project supported by the Open Fund of Advanced Cryptography and System Security Key Laboratory of Sichuan Province,China(Grant No.SKLACSS-202108)the Open Research Fund of Key Laboratory of Cryptography of Zhejiang Province,China(Grant No.ZCL21006)+3 种基金the National Natural Science Foundation of China(Grant Nos.U1636106,92046001,61671087,61962009,and 61170272)the BUPT Excellent Ph.D.Students Foundation(Grant No.CX2020310)Natural Science Foundation of Beijing Municipality,China(Grant No.4182006)the Fundamental Research Funds for the Central Universities,China(Grant No.2019XD-A02).
文摘Very recently,Lee et al.proposed a secure quantum teleportation protocol to transfer shared quantum secret between multiple parties in a network[Phys.Rev.Lett.124060501(2020)].This quantum network is encoded with a maximally entangled GHZ state.In this paper,we consider a partially entangled GHZ state as the entanglement channel,where it can achieve,probabilistically,unity fidelity transfer of the state.Two kinds of strategies are given.One arises when an auxiliary particle is introduced and a general evolution at any receiver's location is then adopted.The other one involves performing a single generalized Bell-state measurement at the location of any sender.This could allow the receivers to recover the transmitted state with a certain probability,in which only the local Pauli operators are performed,instead of introducing an auxiliary particle.In addition,the successful probability is provided,which is determined by the degree of entanglement of the partially multipartite entangled state.Moreover,the proposed protocol is robust against the bit and phase flip noise.
基金supported by the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302401)the Hunan Provincial Science Foundation for Distinguished Young Scholars(Grant No.2021JJ10043)the Open Research Fund from State Key Laboratory of High Performance Computing of China(HPCL)(Grant No.201901-09).
文摘The synthetic Floquet lattice,generated by multiple strong drives with mutually incommensurate frequencies,provides a powerful platform for quantum simulation of topological phenomena.In this study,we propose a 4-band tight-binding model of the Chern insulator with a Chern number C=±2 by coupling two layers of the half Bernevig–Hughes–Zhang lattice and subsequently mapping it onto the Floquet lattice to simulate its topological properties.To determine the Chern number of our Floquet-version model,we extend the energy pumping method proposed by Martin et al.[2017 Phys.Rev.X 7041008]and the topological oscillation method introduced by Boyers et al.[2020 Phys.Rev.Lett.125160505],followed by numerical simulations for both methodologies.The simulation results demonstrate the successful extraction of the Chern number using either of these methods,providing an excellent prediction of the phase diagram that closely aligns with the theoretical one derived from the original bilayer half Bernevig–Hughes–Zhang model.Finally,we briefly discuss a potential experimental implementation for our model.Our work demonstrates significant potential for simulating complex topological matter using quantum computing platforms,thereby paving the way for constructing a more universal simulator for non-interacting topological quantum states and advancing our understanding of these intriguing phenomena.
文摘A pioneering chip-based quantum digital signature(QDS)network achieves secure document signing over 200 km of fiber,leveraging integrated photonics to miniaturize transmitters and centralize measurement systems.This breakthrough paves the way for future scalable,cost-effective,and robust quantum-secure communication networks.
基金Project supported by the Romanian Ministry of Research and Innovation under grant agreement no.16N/2019 within Program NUCLEULAPLASⅥ(PN-Ⅲ-P1-1.1-PD-2019-0665,PN-Ⅲ-P4-ID-PCE-2020-2203)。
文摘In this work,calcium niobium gallium garnet(Ca_(3)Nb_(1.6875)Ga_(3.1875)O_(12)-CNGG)ceramic samples singledoped with Tb^(3+)and co-doped with Tb^(3+)and Yb^(3+)ions were sintered by the solid-state reaction method.The structural characterization of the samples was carried out by X-ray diffraction measurements.The optimal concentration of Tb^(3+)ions corresponding to the maximum luminescence in the green spectral range in CNGG:x at%Tb(x=0.1,0.5,1,2,3,4,and 5)was determined to be 4 at%.The timeresolved luminescence of the^(5)D_(4)level(Tb^(3+))in the CNGG:x at%Tb samples was analysed to explore the quenching mechanisms involved in the Tb^(3+)green emission.Co-doped CNGG:4 at%Tb,y at%Yb(y=0.5,2,4,6,8,and 10)ceramics were prepared and investigated.It is shown that CNGG:4 at%Tb,y at%Yb phosphors exhibit intense green luminescence under ultra-violet(UV),visible(VIS),and near-infrared(NIR)excitation,thus demonstrating the presence of simultaneous down-conversion(DC)and upconversion(UC)processes.The dependence of the UC luminescence intensity on the diode laser pumping power was measured and the results indicate a two-photon process based on cooperative energy transfer(CET).Under UV excitation,the lifetime of the^(5)D_(4)(Tb^(3+))level slowly increases with increase of Yb^(3+)concentration,suggesting the energy transfer from Yb^(3+)to Tb^(3+)ions,while under NIR excitation,the lifetime of the^(5)D_(4)(Tb^(3+))level decreases with increase of Yb^(3+)ions concentration,indicating the presence of a strong energy transfer from Tb^(3+)to Yb^(3+)ions.The highest energy transfer efficiency ofη_(ET)≈42%was determined for the CNGG:4 at%Tb,10 at%Yb sample.The obtained results indicate that CNGG:(Tb^(3+),Yb^(3+))could be efficient new yellowish-green-emitting phosphors.
基金Supported by the National Natural Science Foundation of China under Grant No 60576042, and the Natural Science Foundation of Zhejiang Province （Y105426）.
文摘We experimentally demonstrate perfect discrimination between two unitary operations by using the sequential scheme proposed by Duan et al.[Phys. Rev. Lett. 98 （2007） 100503] Also, we show how to understand the scheme and to calculate the parameters for two-dimensional operations in the picture of the Bloch sphere.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11074026, 11074155, and 11104225)the Program for New Century Excellent Talents in University of the Ministry of Education of China (Grant No. NCET-08-0883)the National Basic Research Program of China (Grant No. 2011CB808100)
文摘Nonsequential double ionization （NSDI） processes of nonaligned diatomic molecules N2 and O2 are studied using the S-matrix theory. Our results show that the NSDI process significantly depends on the molecular symmetry and structure. The ratio of NSDI rate to single ionization rate as a function of the field intensity is obtained. It is found that N2 behaves closely with its companion atom Ar in the ratios over the entire intensity range, while O2 exhibits an obvious suppression effect, which is qualitatively consistent with the experiment.
基金Project supported by the National Natural Science Foundation of China(Grant No.11974290)the Fundamental Research Funds for the Central Universities,China(Grant No.2232020D-44).
文摘Metasurface is a kind of two-dimensional metamaterial with specially designed sub-wavelength unit cells.It consists of single-layer or few-layer stacks of planar structures and possesses certain superior abilities to manipulate the propagating electromagnetic waves,including the terahertz(THz)ones.Compared with the usual passive THz metasurfaces whose optical properties are difficult to be controlled after fabrication,the active materials are highly desirable to enable dynamic and tunable control of THz waves.In this review,we briefly summarize the progress of active THz metasurfaces,from their physical mechanisms on carrier concentration modulations,phase transitions,magneto-optical effects,etc.,for various possible THz applications mainly with low-dimensional materials,vanadium dioxide films,and superconductors.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61308008 and U1330201)
文摘Hardy＇s theorem on nonlocality has been verified by a series of experiments with two-qubit entangled pure states.However,in this paper we demonstrate the experimental test of the theorem by using the two-photon entangled mixed states.We first investigate the generic logic in Hardy＇s proof of nonlocality,which can be applied for arbitrary two-qubit mixed polarization entangled states and can be reduced naturally to the well-known logic tested successfully by the previous pure state experiments.Then,the optimized violations of locality for various experimental parameters are delivered by the numerical method.Finally,the logic argued above for testing Hardy＇s theorem on nonlocality is demonstrated experimentally by using the mixed entangled-photon pairs generated via pumping two type-I BBO crystals.Our experimental results shows that Hardy＇s proof of nonlocality can also be verified with two-qubit polarization entangled mixed states,with a violation of about 3.4 standard deviations.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11204249,11174373the National Fundamental Research Program of China under Grant No.2010CB923104
文摘The system of electrons on liquid helium is an interesting candidate to implement quantum computation, due to the long coherence times of the qubits encoded by the electronic spins. In order to implement the quantum logic operations between the spins, we propose here a configuration, similarly to the cooled ions in a trap, to couple the distant electrons via manipulating their center of mass （CM） vibrations. First, we show that the electrons could be confined in a common harmonic oscillator potential by using an electrostatic field. Then, with a single current pulse （applied on the micro-electrode below the liquid helium） the distant electronic spins can be coupled simultaneously to the CM mode. Finally, by adiabatically eliminating the CM mode, effective interaction between the distant spins is induced for implementing the desired quantum computing.
文摘A cold atomic medium(Rydberg medium) with cascade configuration under the blockade mechanism is considered. A partial coherent light(PCL) beam is incident on the medium, which makes an angle θ with z-axis. We study the influence of PCL field on the transmission spectrum and find high transmission of probe field for PCL field.Conversely, it is investigated that the transparency of probe field decrease for coherent light field. The transmission of probe field is also studied via beam width of PCL field and investigated high transmission of probe field for small beam width and vice versa. Interestingly, the Goos-H?nchen shift(GHS) in the transmitted light(TL) is studied for PCL field. Large negative and positive GHS in the TL are investigated for PCL field and small beam width of PCL field.
基金Project supported by the Industry Key Technologies R & D Project in Shaanxi Province of China (Grant No. 2012K07-19)
文摘Recently, individual reduced-symmetry metal nanostructures and their plasmonic properties have been studied extensively. However, little attention has been paid to the approach to fabricating ordered reduced-symmetry metal nanostructure arrays. In this paper, a novel perforated silver nanocap array with high surface-enhanced Raman scattering （SERS） activity and fluorescence suppression is reported. The array is fabricated by electron beam evaporating Ag onto the perforated barrier layer side of a hard anodization （HA） anodic aluminum oxide （AAO） template. The morphology and optical property of the perforated silver nanocap array are characterized by an atomic force microscope （AFM）, a scanning electron microscope （SEM）, and absorption spectra. The results of SERS measurements reveal that the perforated silver nanocap array offers high SERS activity and fluorescence suppression compared with an imperforated silver nanocap array.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10847006 and 10874142
文摘We investigate the self-trapping of a Bose Josephson junction, which is dispersively coupled to a driven optical cavity. The cavity-induced nonlinearity is presented analytically, and its effect results in the appearance of the self-trapping for the Bose-Einstein condensates in the Josephson oscillation regime. In addition, there exists competition between the nonlinearities induced by the interatomic interaction and by the driven cavity for the emergences of self-trapping. Our results show that the driven cavity can be utilized as a possible tool to produce the self-trapping for the condensates with weak interatomic interaction.
文摘<span style="white-space:normal;">The study of high dielectric materials has received great attention lately as a key passive component for the application of metal-insulator-metal (MIM) capacitors. In this paper, 50 nm thick Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;"> thin films have been prepared by atomic layer deposition technique on indium tin oxide (ITO) pre-coated glass substrates and titanium nitride (TiN) coated Si substrates with typical MIM capacitor structure. Photolithography and metal lift-off technique were used for processing of the MIM capacitors. Semiconductor Analyzer with probe station was used to perform capacitance-voltage (C-V) characterization with low-medium frequency range. Current-voltage (I-V) characteristics of MIM capacitors were measured on precision source/measurement system. The performance of Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;"> films of MIM capacitors on glass was examined in the voltage range from <span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span>5 to 5 V with a frequency range from 10 kHz to 5 MHz. Au/Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;">/ITO/Glass MIM capacitors demonstrate a capacitance density of 1.6 fF/μm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;">at 100 kHz, a loss tangent ~0.005 at 100 kHz and a leakage current of 1.79 × 10</span><sup style="white-space:normal;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span>8</sup><span style="white-space:normal;"> A/cm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;"> at 1 MV/cm (5 V) at room temperature. Au/Al</span><sub style="white-space:normal;">2</sub><span style="white-space:normal;">O</span><sub style="white-space:normal;">3</sub><span style="white-space:normal;">/TiN/Si MIM capacitors demonstrate a capacitance density of 1.5 fF/μm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;"> at 100 kHz, a loss tangent ~0.007 at 100 kHz and a lower leakage current of 2.93 × 10</span><sup style="white-space:normal;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span>10</sup><span style="white-space:normal;"> A/cm</span><sup style="white-space:normal;">2</sup><span style="white-space:normal;"> at 1 MV/cm (5 V) at room temperature. The obtained electrical properties could indicate a promising application of MIM Capacitors.</span>
