Phase-coherent multi-tone lasers play a critical role in atomic,molecular,and optical physics.Among them,the Raman opeartion laser for manipulating atomic hyperfine qubits requires gigahertz bandwidth and low phase no...Phase-coherent multi-tone lasers play a critical role in atomic,molecular,and optical physics.Among them,the Raman opeartion laser for manipulating atomic hyperfine qubits requires gigahertz bandwidth and low phase noise to retain long-term coherence.Raman operation lasers generated by directly modulated and frequency-multipled infrared lasers are compact and stable but lack feedback control to actively suppress the phase noise,which limits their performance in practical applications.In this work,we employ a fiber electro-optical modulator driven by a voltage-controlled oscillator(VCO)to modulate a monochromatic laser and employ a second-harmonic generation process to convert it to the visible domain,where the beat note of the Raman operation laser is stabilized by controlling the output frequency of VCO with a digital phase-locked loop(PLL).The low-frequency phase noise is effectively suppressed compared to the scheme without active feedback and it reaches-80 d Bc/Hz@5 k Hz with a 20 k Hz loop bandwidth.Furthermore,this compact and robust scheme effectively reduces the system's complexity and cost,which is promising for extensive application in atomic,molecular,and optical physics.展开更多
Weak measurement amplification,which is considered as a very promising scheme in precision measurement,has been applied to various small physical quantities estimations.Since many physical quantities can be converted ...Weak measurement amplification,which is considered as a very promising scheme in precision measurement,has been applied to various small physical quantities estimations.Since many physical quantities can be converted into phase signals,it is interesting and important to consider measuring small longitudinal phase shifts by using weak measurement.Here,we propose and experimentally demonstrate a novel weak measurement amplification-based small longitudinal phase estimation,which is suitable for polarization interferometry.We realize one order of magnitude amplification measurement of a small phase signal directly introduced by a liquid crystal variable retarder and show that it is robust to the imperfection of interference.Besides,we analyze the effect of magnification error which is never considered in the previous works,and find the constraint on the magnification.Our results may find important applications in high-precision measurements,e.g.,gravitational wave detection.展开更多
The cavity quantum electrodynamics (QED) system is a promising platform for quantum optics and quantum information experiments.Its core is the strong coupling between atoms and optical cavity,which causes difficulty i...The cavity quantum electrodynamics (QED) system is a promising platform for quantum optics and quantum information experiments.Its core is the strong coupling between atoms and optical cavity,which causes difficulty in the overlap between the atoms and the antinode of optical cavity mode.Here,we use a programmable movable optical dipole trap to load a cold atomic ensemble into an optical fiber microcavity and realize the strong coupling between the atoms and the optical cavity in which the coupling strength can be improved by polarization gradient cooling and adiabatic loading.By the measurement of vacuum Rabi splitting,the coupling strength can be as high as g_(N)=2π×400 MHz,which means the effective atom number is N_(eff)=16 and the collective cooperativity is C_(N)=1466.These results show that this experimental system can be used for cold atomic ensemble and cold molecule based cavity QED research.展开更多
Trapped atoms on photonic structures inspire many novel quantum devices for quantum information processing and quantum sensing.Here,we demonstrate a hybrid photonic-atom chip platform based on a Ga N-onsapphire chip a...Trapped atoms on photonic structures inspire many novel quantum devices for quantum information processing and quantum sensing.Here,we demonstrate a hybrid photonic-atom chip platform based on a Ga N-onsapphire chip and the transport of an ensemble of atoms from free space towards the chip with an optical conveyor belts.Due to our platform’s complete optical accessibility and careful control of atomic motion near the chip with a conveyor belt,successful atomic transport towards the chip is made possible.The maximum transport efficiency of atoms is about 50%with a transport distance of 500μm.Our results open up a new route toward the efficient loading of cold atoms into the evanescent-field trap formed by the photonic integrated circuits,which promises strong and controllable interactions between single atoms and single photons.展开更多
Spin qubits and superconducting qubits are promising candidates for realizing solid-state quantum information processors.Designing a hybrid architecture that combines the advantages of different qubits on the same chi...Spin qubits and superconducting qubits are promising candidates for realizing solid-state quantum information processors.Designing a hybrid architecture that combines the advantages of different qubits on the same chip is a highly desirable but challenging goal.Here we propose a hybrid architecture that utilizes a high-impedance SQUID array resonator as a quantum bus,thereby coherently coupling different solid-state qubits.We employ a resonant exchange spin qubit hosted in a triple quantum dot and a superconducting transmon qubit.Since this hybrid system is highly tunable,it can operate in a dispersive regime,where the interaction between the different qubits is mediated by virtual photons.By utilizing such interactions,entangling gate operations between different qubits can be realized in a short time of 30 ns with a fidelity of up to 96.5%under realistic parameter conditions.Further utilizing this interaction,remote entangled state between different qubits can be prepared and is robust to perturbations of various parameters.These results pave the way for exploring efficient fault-tolerant quantum computation on hybrid quantum architecture platforms.展开更多
基金supported by the National Key Research and Development Program of China(No.2017YFA0304100)National Natural Science Foundation of China(Nos.11774335,11734015,and 12204455)+1 种基金the Key Research Program of Frontier Sciences,CAS(No.QYZDY-SSWSLH003)Innovation Program for Quantum Science and Technology(Nos.2021ZD0301604 and 2021ZD0301200)。
文摘Phase-coherent multi-tone lasers play a critical role in atomic,molecular,and optical physics.Among them,the Raman opeartion laser for manipulating atomic hyperfine qubits requires gigahertz bandwidth and low phase noise to retain long-term coherence.Raman operation lasers generated by directly modulated and frequency-multipled infrared lasers are compact and stable but lack feedback control to actively suppress the phase noise,which limits their performance in practical applications.In this work,we employ a fiber electro-optical modulator driven by a voltage-controlled oscillator(VCO)to modulate a monochromatic laser and employ a second-harmonic generation process to convert it to the visible domain,where the beat note of the Raman operation laser is stabilized by controlling the output frequency of VCO with a digital phase-locked loop(PLL).The low-frequency phase noise is effectively suppressed compared to the scheme without active feedback and it reaches-80 d Bc/Hz@5 k Hz with a 20 k Hz loop bandwidth.Furthermore,this compact and robust scheme effectively reduces the system's complexity and cost,which is promising for extensive application in atomic,molecular,and optical physics.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 92065113, 11904357, 62075208, and 12174367)the Innovation Programme for Quantum Science and Technology (Grant No. 2021ZD0301604)+1 种基金the National Key Research and Development Program of China (Grant No. 2021YFE0113100)supported by Beijing Academy of Quantum Information Sciences
文摘Weak measurement amplification,which is considered as a very promising scheme in precision measurement,has been applied to various small physical quantities estimations.Since many physical quantities can be converted into phase signals,it is interesting and important to consider measuring small longitudinal phase shifts by using weak measurement.Here,we propose and experimentally demonstrate a novel weak measurement amplification-based small longitudinal phase estimation,which is suitable for polarization interferometry.We realize one order of magnitude amplification measurement of a small phase signal directly introduced by a liquid crystal variable retarder and show that it is robust to the imperfection of interference.Besides,we analyze the effect of magnification error which is never considered in the previous works,and find the constraint on the magnification.Our results may find important applications in high-precision measurements,e.g.,gravitational wave detection.
基金supported by the Innovation Program for Quantum Science and Technology (No.2021ZD0301200)the National Natural Science Foundation of China (Nos.11804330 and 11821404)the Fundamental Research Funds for the Central Universities (WK2470000038)。
文摘The cavity quantum electrodynamics (QED) system is a promising platform for quantum optics and quantum information experiments.Its core is the strong coupling between atoms and optical cavity,which causes difficulty in the overlap between the atoms and the antinode of optical cavity mode.Here,we use a programmable movable optical dipole trap to load a cold atomic ensemble into an optical fiber microcavity and realize the strong coupling between the atoms and the optical cavity in which the coupling strength can be improved by polarization gradient cooling and adiabatic loading.By the measurement of vacuum Rabi splitting,the coupling strength can be as high as g_(N)=2π×400 MHz,which means the effective atom number is N_(eff)=16 and the collective cooperativity is C_(N)=1466.These results show that this experimental system can be used for cold atomic ensemble and cold molecule based cavity QED research.
基金supported by the National Natural Science Foundation of China(11821404,11804330)the Key Research Program of Frontier Sciences,CAS(QYZDY-SSW-SLH003)+3 种基金the Science Foundation of the CAS(ZDRW-XH2019-1)the Fundamental Research Funds for the Central Universities(WK2470000026,WK2470000027,WK2470000028,WK2470000038)the Anhui Initiative in Quantum Information Technologies(AHY020100)the National Program for Support of Topnotch Young Professionals(BB2470000005).
基金supported by the National Key R&D Program(Grant No.2021YFF0603701)the National Natural Science Foundation of China(Grant Nos.U21A20433,U21A6006,92265210,12104441,12134014,61905234,and 11974335)+1 种基金the USTC Research Funds of the Double First-Class Initiative(Grant No.YD2030002007),USTC Research Funds of the Double First-Class Initiativesupported by the Fundamental Research Funds for the Central Universities。
文摘Trapped atoms on photonic structures inspire many novel quantum devices for quantum information processing and quantum sensing.Here,we demonstrate a hybrid photonic-atom chip platform based on a Ga N-onsapphire chip and the transport of an ensemble of atoms from free space towards the chip with an optical conveyor belts.Due to our platform’s complete optical accessibility and careful control of atomic motion near the chip with a conveyor belt,successful atomic transport towards the chip is made possible.The maximum transport efficiency of atoms is about 50%with a transport distance of 500μm.Our results open up a new route toward the efficient loading of cold atoms into the evanescent-field trap formed by the photonic integrated circuits,which promises strong and controllable interactions between single atoms and single photons.
基金supported by the Innovation Program for Quantum Science and Technology (2021ZD0301400)the National Natural Science Foundation of China (61725504, 11774335, 11821404, U19A2075)+1 种基金the Fundamental Research Funds for the Central Universities ( WK2030380017, WK2030000056)Anhui Initiative in Quantum Information Technologies (AHY020100, AHY060300)
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11974336 and 12304401)the National Key R&D Program of China(Grant No.2017YFA0304100)+1 种基金the Key Project of Natural Science Research in Universities of Anhui Province(Grant No.KJ2021A1107)the Scientific Research Foundation of Suzhou University(Grant Nos.2020BS006 and 2021XJPT18).
文摘Spin qubits and superconducting qubits are promising candidates for realizing solid-state quantum information processors.Designing a hybrid architecture that combines the advantages of different qubits on the same chip is a highly desirable but challenging goal.Here we propose a hybrid architecture that utilizes a high-impedance SQUID array resonator as a quantum bus,thereby coherently coupling different solid-state qubits.We employ a resonant exchange spin qubit hosted in a triple quantum dot and a superconducting transmon qubit.Since this hybrid system is highly tunable,it can operate in a dispersive regime,where the interaction between the different qubits is mediated by virtual photons.By utilizing such interactions,entangling gate operations between different qubits can be realized in a short time of 30 ns with a fidelity of up to 96.5%under realistic parameter conditions.Further utilizing this interaction,remote entangled state between different qubits can be prepared and is robust to perturbations of various parameters.These results pave the way for exploring efficient fault-tolerant quantum computation on hybrid quantum architecture platforms.
