We propose schemes to realize quantum state transfer and prepare quantum entanglement in coupled cavity and cavity-fiber-cavity systems,respectively,by using the dressed state method.We first give the expression of pu...We propose schemes to realize quantum state transfer and prepare quantum entanglement in coupled cavity and cavity-fiber-cavity systems,respectively,by using the dressed state method.We first give the expression of pulses shape by using dressed states and then find a group of Gaussian pulses that are easy to realize in experiment to replace the ideal pulses by curve fitting.We also study the influence of some parameters fluctuation,atomic spontaneous emission,and photon leakage on fidelity.The results show that our schemes have good robustness.Because the atoms are trapped in different cavities,it is easy to perform different operations on different atoms.The proposed schemes have the potential applications in dressed states for distributed quantum information processing tasks.展开更多
Kerr nonlinearity is an important resource for creating squeezing and entanglement in quantum technology.Here we propose a scheme for generating Kerr nonlinearity originated from an engineered non-Markovian environmen...Kerr nonlinearity is an important resource for creating squeezing and entanglement in quantum technology.Here we propose a scheme for generating Kerr nonlinearity originated from an engineered non-Markovian environment,which is different from the previous efforts using nonlinear media or quantum systems with special energy structures.In the present work,the generation of Kerr nonlinearity depends on the system-environment interaction time,the energy spectrum of the environment,and the system-environment coupling strength,regardless of the environmental initial state.The scheme can be realized in systems originally containing no Kerr interaction,such as superconducting circuit systems,optomechanical systems,and cavity arrays connected by transmission lines.展开更多
Trapped ions, under electromagnetic confinement and Coulomb repulsion, can behave as non-interacting particles in one-dimensional lattices. Here we explore analytically the possible effects regarding Anderson localiza...Trapped ions, under electromagnetic confinement and Coulomb repulsion, can behave as non-interacting particles in one-dimensional lattices. Here we explore analytically the possible effects regarding Anderson localization in a chain of trapped ions experiencing laser Bessel beams. Under an experimentally feasible condition, we predict an analytical form of the energy-dependent mobility edges, which is verified to be in good agreement with the exact numerical results except for the top band. Some other important properties regarding the phonon localization in the ion chain are also discussed both analytically and numerically. Our results are relevant to experimental observation of localization–delocalization transition in the ion trap and helpful for deeper understanding of the rich phenomena due to long-range phonon hopping.展开更多
The trapped ions confined in a surface-electrode trap(SET)could be free from rf heating if they stay at the rf potential null of the potential well.We report our effort to compensate three-dimensionally for the microm...The trapped ions confined in a surface-electrode trap(SET)could be free from rf heating if they stay at the rf potential null of the potential well.We report our effort to compensate three-dimensionally for the micromotion of a single ^40Ca^+ion near the rf potential null,which largely suppresses the ion’s heating and thus helps to achieve the cooling of the ion down to 3.4 mK,which is very close to the Doppler limit.This is the prerequosite of the sideband cooling in our SET.展开更多
Vibrational resonances are ubiquitous in various nonlinear systems and play crucial roles in detecting weak low-frequency signals and developing highly sensitive sensors.Here we demonstrate vibrational resonance,for t...Vibrational resonances are ubiquitous in various nonlinear systems and play crucial roles in detecting weak low-frequency signals and developing highly sensitive sensors.Here we demonstrate vibrational resonance,for the first time,utilizing a single-ion phonon laser system exhibiting Van der Pol-type nonlinearity.To enhance the response of the phonon laser system to weak signals,we experimentally realize continuously tunable symmetry of the bistability in the phonon laser system via optical modulation,and achieve the maximum vibrational resonance amplification of 23 dB.In particular,our single-ion phonon laser system relaxes the frequency separation condition and exhibits the potential of multifrequency signal amplification using the vibrational resonance.Our study employs the phonon laser to study and optimize the vibrational resonance with simple and well-controllable optical technology,which holds potential applications in developing precision metrology and single-ion sensors with on-chip ion traps.展开更多
Quantum heat engines and refrigerators are open quantum systems,whose dynamics can be well understood using a non-Hermitian formalism.A prominent feature of non-Hermiticity is the existence of exceptional points(EPs),...Quantum heat engines and refrigerators are open quantum systems,whose dynamics can be well understood using a non-Hermitian formalism.A prominent feature of non-Hermiticity is the existence of exceptional points(EPs),which has no counterpart in closed quantum systems.It has been shown in classical systems that dynamical encirclement in the vicinity of an EP,whether the loop includes the EP or not,could lead to chiral mode conversion.Here,we show that this is valid also for quantum systems when dynamical encircling is performed in the vicinity of their Liouvillian EPs(LEPs),which include the effects of quantum jumps and associated noise—an important quantum feature not present in previous works.We demonstrate,using a Paul-trapped ultracold ion,the first chiral quantum heating and refrigeration by dynamically encircling a closed loop in the vicinity of an LEP.We witness the cycling direction to be associated with the chirality and heat release(absorption)of the quantum heat engine(quantum refrigerator).Our experiments have revealed that not only the adiabaticity breakdown but also the Landau–Zener–Stückelberg process play an essential role during dynamic encircling,resulting in chiral thermodynamic cycles.Our observations contribute to further understanding of chiral and topological features in non-Hermitian systems and pave a way to exploring the relation between chirality and quantum thermodynamics.展开更多
Detecting extremely small forces helps exploring new physics quantitatively.Here we demonstrate that the phonon laser made of a single trapped ^(40)Ca^(+) ion behaves as an exquisite sensor for small force measurement...Detecting extremely small forces helps exploring new physics quantitatively.Here we demonstrate that the phonon laser made of a single trapped ^(40)Ca^(+) ion behaves as an exquisite sensor for small force measurement.We report our successful detection of small electric forces regarding the DC trapping potential with sensitivity of(2.41±0.49)zN/√Hz,with the ion only under Doppler cooling,based on the injection-locking of the oscillation phase of the phonon laser in addition to the classical squeezing applied to suppress the measurement uncertainty.We anticipate that such a single-ion sensor would reach a much better force detection sensitivity in the future once the trapping system is further improved and the fluorescence collection efficiency is further enhanced.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11804308).
文摘We propose schemes to realize quantum state transfer and prepare quantum entanglement in coupled cavity and cavity-fiber-cavity systems,respectively,by using the dressed state method.We first give the expression of pulses shape by using dressed states and then find a group of Gaussian pulses that are easy to realize in experiment to replace the ideal pulses by curve fitting.We also study the influence of some parameters fluctuation,atomic spontaneous emission,and photon leakage on fidelity.The results show that our schemes have good robustness.Because the atoms are trapped in different cavities,it is easy to perform different operations on different atoms.The proposed schemes have the potential applications in dressed states for distributed quantum information processing tasks.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0304503)the National Natural Science Foundation of China(Grant Nos.11835011,11574353,11734018,and 11674360)。
文摘Kerr nonlinearity is an important resource for creating squeezing and entanglement in quantum technology.Here we propose a scheme for generating Kerr nonlinearity originated from an engineered non-Markovian environment,which is different from the previous efforts using nonlinear media or quantum systems with special energy structures.In the present work,the generation of Kerr nonlinearity depends on the system-environment interaction time,the energy spectrum of the environment,and the system-environment coupling strength,regardless of the environmental initial state.The scheme can be realized in systems originally containing no Kerr interaction,such as superconducting circuit systems,optomechanical systems,and cavity arrays connected by transmission lines.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11734018,11674360,11404377,and 91636220)
文摘Trapped ions, under electromagnetic confinement and Coulomb repulsion, can behave as non-interacting particles in one-dimensional lattices. Here we explore analytically the possible effects regarding Anderson localization in a chain of trapped ions experiencing laser Bessel beams. Under an experimentally feasible condition, we predict an analytical form of the energy-dependent mobility edges, which is verified to be in good agreement with the exact numerical results except for the top band. Some other important properties regarding the phonon localization in the ion chain are also discussed both analytically and numerically. Our results are relevant to experimental observation of localization–delocalization transition in the ion trap and helpful for deeper understanding of the rich phenomena due to long-range phonon hopping.
基金National Natural Science Foundation of China(Grant Nos.11734018 and 11674360)。
文摘The trapped ions confined in a surface-electrode trap(SET)could be free from rf heating if they stay at the rf potential null of the potential well.We report our effort to compensate three-dimensionally for the micromotion of a single ^40Ca^+ion near the rf potential null,which largely suppresses the ion’s heating and thus helps to achieve the cooling of the ion down to 3.4 mK,which is very close to the Doppler limit.This is the prerequosite of the sideband cooling in our SET.
文摘Vibrational resonances are ubiquitous in various nonlinear systems and play crucial roles in detecting weak low-frequency signals and developing highly sensitive sensors.Here we demonstrate vibrational resonance,for the first time,utilizing a single-ion phonon laser system exhibiting Van der Pol-type nonlinearity.To enhance the response of the phonon laser system to weak signals,we experimentally realize continuously tunable symmetry of the bistability in the phonon laser system via optical modulation,and achieve the maximum vibrational resonance amplification of 23 dB.In particular,our single-ion phonon laser system relaxes the frequency separation condition and exhibits the potential of multifrequency signal amplification using the vibrational resonance.Our study employs the phonon laser to study and optimize the vibrational resonance with simple and well-controllable optical technology,which holds potential applications in developing precision metrology and single-ion sensors with on-chip ion traps.
基金the Special Project for Research and Development in Key Areas of Guangdong Province under Grant No.2020B0303300001Guangdong Provincial Quantum Science Strategic Initiative under Grant No.GDZX2305004+9 种基金the National Natural Science Foundation of China under Grant Nos.U21A20434,92265107,12074390,11835011Key Lab of Guangzhou for Quantum Precision Measurement under Grant No.202201000010Postdoctoral Science Foundation of China under Grant No.2022MT10881Nansha Senior Leading Talent Team Technology Project under Grant No.2021CXTD02Ş.K.O.acknowledges the support from the Air Force Office of Scientific Research(AFOSR)Multidisciplinary University Research Initiative(MURI)Award No.FA9550-21-1-0202the AFOSR Award No.FA9550-18-1-0235H.J.is supported by the NSFC(11935006)the Science and Technology Innovation Program of Hunan Province(Grant No.2020RC4047)National Key R&D Program of China(No.2024YFE0102400)Hunan provincial major sci-tech program(2023ZJ1010).
文摘Quantum heat engines and refrigerators are open quantum systems,whose dynamics can be well understood using a non-Hermitian formalism.A prominent feature of non-Hermiticity is the existence of exceptional points(EPs),which has no counterpart in closed quantum systems.It has been shown in classical systems that dynamical encirclement in the vicinity of an EP,whether the loop includes the EP or not,could lead to chiral mode conversion.Here,we show that this is valid also for quantum systems when dynamical encircling is performed in the vicinity of their Liouvillian EPs(LEPs),which include the effects of quantum jumps and associated noise—an important quantum feature not present in previous works.We demonstrate,using a Paul-trapped ultracold ion,the first chiral quantum heating and refrigeration by dynamically encircling a closed loop in the vicinity of an LEP.We witness the cycling direction to be associated with the chirality and heat release(absorption)of the quantum heat engine(quantum refrigerator).Our experiments have revealed that not only the adiabaticity breakdown but also the Landau–Zener–Stückelberg process play an essential role during dynamic encircling,resulting in chiral thermodynamic cycles.Our observations contribute to further understanding of chiral and topological features in non-Hermitian systems and pave a way to exploring the relation between chirality and quantum thermodynamics.
基金supported by the Special Project for Research and Development in Key Areas of Guangdong Province(Grant No.2020B0303300001)National Key Research&Development Program of China(Grant No.2017YFA0304503)National Natural Science Foundation of China(Grant Nos.U21A20434,12074390,11835011,and 11734018)。
文摘Detecting extremely small forces helps exploring new physics quantitatively.Here we demonstrate that the phonon laser made of a single trapped ^(40)Ca^(+) ion behaves as an exquisite sensor for small force measurement.We report our successful detection of small electric forces regarding the DC trapping potential with sensitivity of(2.41±0.49)zN/√Hz,with the ion only under Doppler cooling,based on the injection-locking of the oscillation phase of the phonon laser in addition to the classical squeezing applied to suppress the measurement uncertainty.We anticipate that such a single-ion sensor would reach a much better force detection sensitivity in the future once the trapping system is further improved and the fluorescence collection efficiency is further enhanced.
