We explore the time evolution law of a two-mode squeezed light field(pure state)passing through twin diffusion channels,and we find that the final state is a squeezed chaotic light field(mixed state)with entanglement,...We explore the time evolution law of a two-mode squeezed light field(pure state)passing through twin diffusion channels,and we find that the final state is a squeezed chaotic light field(mixed state)with entanglement,which shows that even though the two channels are independent of each other,since the two modes of the initial state are entangled with each other,the final state remains entangled.Nevertheless,although the squeezing(entanglement)between the two modes is weakened after the diffusion,it is not completely removed.We also highlight the law of photon number evolution.In the calculation process used in this paper,we make full use of the summation method within the ordered product of operators and the generating function formula for two-variable Hermite polynomials.展开更多
We investigate properties of the ponderomotive squeezing in an optomechanical system with two coupled resonators,where the tunable two-mode squeezing spectrum can be observed from the output field.It is realized that ...We investigate properties of the ponderomotive squeezing in an optomechanical system with two coupled resonators,where the tunable two-mode squeezing spectrum can be observed from the output field.It is realized that the squeezing orientation can be controlled by the detuning between the left cavity and pump laser.Especially,both cavity decay and environment temperature play a positive role in generating better pondermotive squeezing light.Strong squeezing spectra with a wide squeezing frequency range can be obtained by appropriate choice of parameters present in our optomechanical system.展开更多
Einstein–Podolski–Rosen（EPR） entanglement state is achievable by combining two single-mode position and momentum squeezed states at a 50：50 beam-splitter（BS）. We investigate the generation of the EPR entangled ...Einstein–Podolski–Rosen（EPR） entanglement state is achievable by combining two single-mode position and momentum squeezed states at a 50：50 beam-splitter（BS）. We investigate the generation of the EPR entangled state of two vibrating membranes in a ring resonator, where clockwise（CW） and counter-clockwise（CCW） travelling-wave modes are driven by lasers and finite-bandwidth squeezed lights. Since the optomechanical coupling depends on the location of the membranes, CW and CCW can couple to the symmetric and antisymmetric combination of mechanical modes for a suitable arrangement, which corresponds to a 50：50 BS mixing. Moreover, by employing the red-detuned driving laser and tuning the central frequency of squeezing field blue detuned from the driving laser with a mechanical frequency, the squeezing property of squeezed light can be perfectly transferred to the mechanical motion in the weak coupling regime. Thus, the BS mixing modes can be position and momentum squeezed by feeding the appropriate squeezed lights respectively, and the EPR entangled mechanical state is obtained. Moreover, cavity-induced mechanical cooling can further suppress the influence of thermal noise on the entangled state.展开更多
It is well known that squeezed states can be produced by nonlinear optical processes,such as parametric amplification and four wave mixing,in which two photons are created or annihilated simultaneously.Since the Hamil...It is well known that squeezed states can be produced by nonlinear optical processes,such as parametric amplification and four wave mixing,in which two photons are created or annihilated simultaneously.Since the Hamiltonian of the dynamic Casimir effect contains a~2 and a~(+2),photons in such a process are also generated or annihilated in pairs.Here we propose to get squeezed light through the dynamic Casimir effect.Specifically,we demonstrate it from the full quantum perspective and the semiclassical perspective successively.Different from previous work,we focus on generating squeezed states with the lowest average photon number,because such squeezed states have better quantum properties.For the full quantum picture,that is,phonons also have quantum properties,when the system is initially in the excited state of phonons,squeezed light cannot be generated during the evolution,but the light field can collapse to the squeezed state by measuring the state of phonons.When the phonon is treated as a classical quantity,that is,the cavity wall is continuously driven,squeezed light with the minimum average photon number will be generated in the case of off-resonance.This will play a positive role in better regulating the photon state generated by the dynamic Casimir system in the future.展开更多
For the density operator（mixed state） describing squeezed chaotic light（SCL） we search for its thermal vacuum state（a pure state） in the real-fictitious space. Using the method of integration within ordered prod...For the density operator（mixed state） describing squeezed chaotic light（SCL） we search for its thermal vacuum state（a pure state） in the real-fictitious space. Using the method of integration within ordered product（IWOP） of operators we find that it is a kind of one- and two-mode combinatorial squeezed state. Its application in evaluating the quantum fluctuation of photon number reveals： the stronger the squeezing is, the larger a fluctuation appears. The second-order degree of coherence of SCL is also deduced which shows that SCL is classic. The new thermal vacuum state also helps to derive the Wigner function of SCL.展开更多
Advancements in quantum optics and squeezed light generation have revolutionized various fields of quantum science over the past three decades,with notable applications such as gravitational wave detection.Here,we ext...Advancements in quantum optics and squeezed light generation have revolutionized various fields of quantum science over the past three decades,with notable applications such as gravitational wave detection.Here,we extend the use of squeezed light to the realm of ultrafast quantum science.We demonstrate the generation of the shortest ultrafast synthesized quantum light pulses spanning 0.33 to 0.73 PHz by a degenerate four-wave mixing nonlinear process.Experimental metrology results confirm that these pulses exhibit amplitude squeezing,which is consistent with theoretical predictions.Moreover,we observe the temporal dynamics of amplitude uncertainty of the squeezed light,demonstrating that quantum uncertainty of light is controllable and tunable in real time.Additionally,we demonstrate control over the quantum state of light by switching between amplitude and phase squeezing.Our ability to generate and manipulate ultrafast,squeezed,synthesized light waveforms with attosecond resolution unlocks exciting possibilities for quantum technologies,including petahertz-scale secure quantum communication,quantum computing,and ultrafast spectroscopy.As an example,we introduce an attosecond quantum encryption protocol leveraging squeezed synthesized light for secure digital communication at unprecedented speeds.This work paves the way for exploring quantum uncertainty dynamics and establishes the foundation for the emerging ultrafast and attosecond quantum science fields.展开更多
The dominant technical noise of a free-running laser practically limits bright squeezed light generation,particularly within the MHz band.To overcome this,we develop a comprehensive theoretical model for nonclassical ...The dominant technical noise of a free-running laser practically limits bright squeezed light generation,particularly within the MHz band.To overcome this,we develop a comprehensive theoretical model for nonclassical power stabilization,and propose a novel bright squeezed light generation scheme incorporating hybrid power noise suppression.Our approach integrates broadband passive power stabilization with nonclassical active stabilization,extending the feedback bandwidth to MHz frequencies.This hybrid technique achieves an additional 9 dB technical noise suppression,establishing critical prerequisites for broadband bright squeezed light generation.Finally,a-5.5 dB bright squeezed light at 1 mW with kHz-MHz squeezing bandwidth was generated.The experimental results show excellent agreement with theoretical predictions,which represent we have comprehensively demonstrated a milliwatt-order bright squeezed light across kHz-MHz frequencies.Our work enables new quantum metrology applications and paves the way for next-generation quantum-enhanced technologies.展开更多
Acceleration sensing, an essential branch of quantum sensing, faces a fundamental trade-off between resolution and bandwidth. Here, we present a quantum-enhanced optomechanical accelerometer(QEOMA), simultaneously ach...Acceleration sensing, an essential branch of quantum sensing, faces a fundamental trade-off between resolution and bandwidth. Here, we present a quantum-enhanced optomechanical accelerometer(QEOMA), simultaneously achieving the improvement of the sensing resolution and bandwidth in contrast with a classical counterpart.By tailoring quantum squeezed light, the optomechanical cooperativity is significantly raised, extending the sensing bandwidth. Quantum squeezed light increases the equivalent Q value of the optomechanical accelerometer owing to the reduction of the mechanical damping rate, driving the resolution improvement at the resonance frequency. At off-resonance frequencies, the resolution improvement is attributed to the imprecision noise reduction. We obtain the measured noise power spectrum and inferred acceleration resolution for the(3,3),(4,4),(5,5), and(6,6) mechanical modes, respectively. The maximum quantum enhancement is measured for the(6,6) mechanical mode with a 38.4% resolution enhancement and 1.55-fold bandwidth broadening in contrast with a coherent probe. The proposed QEOMA shows significant potential for applications ranging from ultralight dark matter searches to inertial navigation of fast-moving objects.展开更多
Squeezed vacuum, as a nonclassical field, has many interesting properties and results in many potential applications for quantum measurement and information processing. Here, we investigate a single atom–cavity quant...Squeezed vacuum, as a nonclassical field, has many interesting properties and results in many potential applications for quantum measurement and information processing. Here, we investigate a single atom–cavity quantum electrodynamics(QED) system driven by a broadband squeezed vacuum. In the presence of the atom, we show that both the mean photon number and the quantum fluctuations of photons in the cavity undergo a significant depletion due to the additional transition pathways generated by the atom–cavity interaction.By measuring these features, one can detect the existence of atoms in the cavity. We also show that two-photon excitation can be significantly suppressed by the quantum destructive interference when the squeezing parameter is very small. These results presented here are helpful in understanding the quantum nature of the broadband squeezed vacuum.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11775208)the Foundation for Young Talents in College of Anhui Province,China(Grant No.gxyq2019077)the Natural Science Foundation of the Anhui Higher Education Institutions of China(Grant Nos.KJ2019A0688 and KJ2020A0638)。
文摘We explore the time evolution law of a two-mode squeezed light field(pure state)passing through twin diffusion channels,and we find that the final state is a squeezed chaotic light field(mixed state)with entanglement,which shows that even though the two channels are independent of each other,since the two modes of the initial state are entangled with each other,the final state remains entangled.Nevertheless,although the squeezing(entanglement)between the two modes is weakened after the diffusion,it is not completely removed.We also highlight the law of photon number evolution.In the calculation process used in this paper,we make full use of the summation method within the ordered product of operators and the generating function formula for two-variable Hermite polynomials.
基金Project supported by the Doctoral Program of Guangdong Natural Science Foundation,China(Grant No.2018A030310109)the Doctoral Project of Guangdong Medical University(Grant No.B2017019)the Project of Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education of China(Grant No.QSQC1808)。
文摘We investigate properties of the ponderomotive squeezing in an optomechanical system with two coupled resonators,where the tunable two-mode squeezing spectrum can be observed from the output field.It is realized that the squeezing orientation can be controlled by the detuning between the left cavity and pump laser.Especially,both cavity decay and environment temperature play a positive role in generating better pondermotive squeezing light.Strong squeezing spectra with a wide squeezing frequency range can be obtained by appropriate choice of parameters present in our optomechanical system.
基金supported by the National Natural Science Foundation of China(Grant Nos.61505014 and 11504031)the Yangtze Youth Talents Fundthe Yangtze Funds for Youth Teams of Science and Technology Innovation(Grant No.2015cqt03)
文摘Einstein–Podolski–Rosen（EPR） entanglement state is achievable by combining two single-mode position and momentum squeezed states at a 50：50 beam-splitter（BS）. We investigate the generation of the EPR entangled state of two vibrating membranes in a ring resonator, where clockwise（CW） and counter-clockwise（CCW） travelling-wave modes are driven by lasers and finite-bandwidth squeezed lights. Since the optomechanical coupling depends on the location of the membranes, CW and CCW can couple to the symmetric and antisymmetric combination of mechanical modes for a suitable arrangement, which corresponds to a 50：50 BS mixing. Moreover, by employing the red-detuned driving laser and tuning the central frequency of squeezing field blue detuned from the driving laser with a mechanical frequency, the squeezing property of squeezed light can be perfectly transferred to the mechanical motion in the weak coupling regime. Thus, the BS mixing modes can be position and momentum squeezed by feeding the appropriate squeezed lights respectively, and the EPR entangled mechanical state is obtained. Moreover, cavity-induced mechanical cooling can further suppress the influence of thermal noise on the entangled state.
基金supported by the National Natural Science Foundation of China (Grant Nos.12174288,12274326,and 12204352)the National Key R&D Program of China (Grant No.2021YFA1400602)。
文摘It is well known that squeezed states can be produced by nonlinear optical processes,such as parametric amplification and four wave mixing,in which two photons are created or annihilated simultaneously.Since the Hamiltonian of the dynamic Casimir effect contains a~2 and a~(+2),photons in such a process are also generated or annihilated in pairs.Here we propose to get squeezed light through the dynamic Casimir effect.Specifically,we demonstrate it from the full quantum perspective and the semiclassical perspective successively.Different from previous work,we focus on generating squeezed states with the lowest average photon number,because such squeezed states have better quantum properties.For the full quantum picture,that is,phonons also have quantum properties,when the system is initially in the excited state of phonons,squeezed light cannot be generated during the evolution,but the light field can collapse to the squeezed state by measuring the state of phonons.When the phonon is treated as a classical quantity,that is,the cavity wall is continuously driven,squeezed light with the minimum average photon number will be generated in the case of off-resonance.This will play a positive role in better regulating the photon state generated by the dynamic Casimir system in the future.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.1117511311447202and 11574295)
文摘For the density operator（mixed state） describing squeezed chaotic light（SCL） we search for its thermal vacuum state（a pure state） in the real-fictitious space. Using the method of integration within ordered product（IWOP） of operators we find that it is a kind of one- and two-mode combinatorial squeezed state. Its application in evaluating the quantum fluctuation of photon number reveals： the stronger the squeezing is, the larger a fluctuation appears. The second-order degree of coherence of SCL is also deduced which shows that SCL is classic. The new thermal vacuum state also helps to derive the Wigner function of SCL.
基金funded by the Gordon and Betty Moore Foundation Grant(GBMF 11476)to M.Hassansupported by the Air Force Office of Scientific Research under award number FA9550-22-1-0494+8 种基金support from:European Research Council AdG NOQIAMCIN/AEI(PGC20180910.13039/501100011033,CEX2019-000910 S/10.13039/501100011033Plan National STAMEENA PID2022-139099NB)project funded by MCIN/AEI/10.13039/501100011033the“European Union Next Generation EU/PRTR”(PRTR-C17.I1),FPI)QUANTERA DYNAMITE PCI2022-132919,Fundació CellexFundació Mir-PuigFundació CellexFundació Mir-Puig.
文摘Advancements in quantum optics and squeezed light generation have revolutionized various fields of quantum science over the past three decades,with notable applications such as gravitational wave detection.Here,we extend the use of squeezed light to the realm of ultrafast quantum science.We demonstrate the generation of the shortest ultrafast synthesized quantum light pulses spanning 0.33 to 0.73 PHz by a degenerate four-wave mixing nonlinear process.Experimental metrology results confirm that these pulses exhibit amplitude squeezing,which is consistent with theoretical predictions.Moreover,we observe the temporal dynamics of amplitude uncertainty of the squeezed light,demonstrating that quantum uncertainty of light is controllable and tunable in real time.Additionally,we demonstrate control over the quantum state of light by switching between amplitude and phase squeezing.Our ability to generate and manipulate ultrafast,squeezed,synthesized light waveforms with attosecond resolution unlocks exciting possibilities for quantum technologies,including petahertz-scale secure quantum communication,quantum computing,and ultrafast spectroscopy.As an example,we introduce an attosecond quantum encryption protocol leveraging squeezed synthesized light for secure digital communication at unprecedented speeds.This work paves the way for exploring quantum uncertainty dynamics and establishes the foundation for the emerging ultrafast and attosecond quantum science fields.
基金sponsored by the National Natural Science Foundation of China(NSFC)(Grant Nos.62225504,U22A6003,62027821,and 62375162)the National Key Research and Development Program of China(No.2024YFF0726401).
文摘The dominant technical noise of a free-running laser practically limits bright squeezed light generation,particularly within the MHz band.To overcome this,we develop a comprehensive theoretical model for nonclassical power stabilization,and propose a novel bright squeezed light generation scheme incorporating hybrid power noise suppression.Our approach integrates broadband passive power stabilization with nonclassical active stabilization,extending the feedback bandwidth to MHz frequencies.This hybrid technique achieves an additional 9 dB technical noise suppression,establishing critical prerequisites for broadband bright squeezed light generation.Finally,a-5.5 dB bright squeezed light at 1 mW with kHz-MHz squeezing bandwidth was generated.The experimental results show excellent agreement with theoretical predictions,which represent we have comprehensively demonstrated a milliwatt-order bright squeezed light across kHz-MHz frequencies.Our work enables new quantum metrology applications and paves the way for next-generation quantum-enhanced technologies.
基金National Natural Science Foundation of China(62225504,12274275,62027821,U22A6003,62375162,12304399,12174234)Key R&D Program of Shanxi(202302150101004).
文摘Acceleration sensing, an essential branch of quantum sensing, faces a fundamental trade-off between resolution and bandwidth. Here, we present a quantum-enhanced optomechanical accelerometer(QEOMA), simultaneously achieving the improvement of the sensing resolution and bandwidth in contrast with a classical counterpart.By tailoring quantum squeezed light, the optomechanical cooperativity is significantly raised, extending the sensing bandwidth. Quantum squeezed light increases the equivalent Q value of the optomechanical accelerometer owing to the reduction of the mechanical damping rate, driving the resolution improvement at the resonance frequency. At off-resonance frequencies, the resolution improvement is attributed to the imprecision noise reduction. We obtain the measured noise power spectrum and inferred acceleration resolution for the(3,3),(4,4),(5,5), and(6,6) mechanical modes, respectively. The maximum quantum enhancement is measured for the(6,6) mechanical mode with a 38.4% resolution enhancement and 1.55-fold bandwidth broadening in contrast with a coherent probe. The proposed QEOMA shows significant potential for applications ranging from ultralight dark matter searches to inertial navigation of fast-moving objects.
基金the National Natural Science Foundation of China(No.11774271).
文摘Squeezed vacuum, as a nonclassical field, has many interesting properties and results in many potential applications for quantum measurement and information processing. Here, we investigate a single atom–cavity quantum electrodynamics(QED) system driven by a broadband squeezed vacuum. In the presence of the atom, we show that both the mean photon number and the quantum fluctuations of photons in the cavity undergo a significant depletion due to the additional transition pathways generated by the atom–cavity interaction.By measuring these features, one can detect the existence of atoms in the cavity. We also show that two-photon excitation can be significantly suppressed by the quantum destructive interference when the squeezing parameter is very small. These results presented here are helpful in understanding the quantum nature of the broadband squeezed vacuum.
