Optical nonreciprocal transmission with unidirectional amplification in a gain-assisted cavity-QED system is investigated.The results demonstrate that unidirectional amplification of this system is induced by the phas...Optical nonreciprocal transmission with unidirectional amplification in a gain-assisted cavity-QED system is investigated.The results demonstrate that unidirectional amplification of this system is induced by the phase difference between the atom-cavity coupling strengths associated with the optical gain and a phase-controlled unidirectional amplifier can be achieved.The optimal parameter conditions for the observation of ideal unidirectional amplification are obtained analytically,and are shown to be dependent on phase,atom-cavity and cavity-cavity coupling strength,and atomic dissipation.In particular,it is found that atomic dissipation is another essential condition for the realization of nonreciprocal amplification other than breaking of the time-reversal symmetry,and our unidirectional amplifier is robust against atom-cavity coupling mismatch.Such unidirectional amplifiers are crucial nonreciprocal devices for controlling photon transmission and may have potential applications in quantum information processing.展开更多
If the singularity of the cosmic Big Bang is taken as the origin of the reference coordinate system,the surrounding vacuum in the initial moments of it would exhibit radially-outward right-handed spiral motion at ligh...If the singularity of the cosmic Big Bang is taken as the origin of the reference coordinate system,the surrounding vacuum in the initial moments of it would exhibit radially-outward right-handed spiral motion at light speed.Based on this spatial motion hypothesis,we derive a unified field equation and a set of Maxwell’s equations for vacuum SWs(Scalar Waves)generating a huge spiral force field that drives the energy to spiral inwardly and distort,leading to the formation of mass.Furthermore,they also uncover that mass is fundamentally an ultimate expression of energy,manifesting as the result of spiral motion of space at light speed.And then,we indirectly validate the theory that coherent light waves’collision generate SWs and subsequently mass through the experiment verifying the Breit-Wheeler process.The establishment of our theory offers a new analytical tool for the exploration of mass origin,the cosmic Big Bang,unified field theories.展开更多
QED(quantum electrodynamics)is the QFT(quantum field theory)describing the interaction between light and matter.While conventional QED is based on TEM(transverse electromagnetic)waves,there has been increasing interes...QED(quantum electrodynamics)is the QFT(quantum field theory)describing the interaction between light and matter.While conventional QED is based on TEM(transverse electromagnetic)waves,there has been increasing interest in the theoretical and experimental exploration of LSW(longitudinal scalar waves)solutions that are often omitted in CED(classical electrodynamics)but may have physical significance in nontrivial vacuum conditions.This paper delves into the theoretical foundation of LSW,their role in QED,and the associated mathematical equations governing their dynamics.展开更多
We investigate phase-controlled bound states in a one-dimensional photonic waveguide coupled to an artificial giant atom at two distant sites. Specifically, we identify the bound state out of the continuum(BOC) and th...We investigate phase-controlled bound states in a one-dimensional photonic waveguide coupled to an artificial giant atom at two distant sites. Specifically, we identify the bound state out of the continuum(BOC) and the bound state in the continuum(BIC) and derive the exact existence condition for the BOC. Furthermore, we analytically determine the BIC's frequency and photonic distribution profile. Remarkably, our analysis reveals quantum beats in both atomic and photonic dynamics, arising from coherent oscillations between the BIC and BOC. These results establish a novel approach for manipulating waveguide quantum electrodynamics via engineered bound states, with potential applications in quantum information processing.展开更多
Waveguide quantum electrodynamics(QED)system manifests an ideal platform for studying many-body physics.When multiple emitters are coupled to a common waveguide,subradiant states may arise because of the waveguide-med...Waveguide quantum electrodynamics(QED)system manifests an ideal platform for studying many-body physics.When multiple emitters are coupled to a common waveguide,subradiant states may arise because of the waveguide-mediated interaction,leading to a long lifetime because of their immunity to the waveguide modeinduced dissipation.However,they can still be influenced by local environments,which are incoherent for different emitters and cannot be canceled out through interference.Herein,a new mechanism termed energy quantum confinement effect(EQCE)is proposed in a non-Markovian waveguide QED system to suppress the local dissipation.The energy quantum is confined in the waveguide by emitters,suppressing spontaneous decay of the emitters.The EQCE makes the system partly free from local dissipation of emitters,leading to a total decay rate lower than the local decay rate.We further show that similar effect occurs spontaneously by self-interference and can be stressed by cooperative coupling,relaxing the requirement for initializing the emitters into a remotely entangled state.展开更多
基金supported by China Postdoctoral Science Foundation(2023M732028)Zhejiang Province Key Laboratory of Quantum Technology and Device(20230201)+1 种基金National Key Research and Development Program of China(2021YFA1400602)National Natural Science Foundation of China(11864018,12164022,12174288,12274326)。
文摘Optical nonreciprocal transmission with unidirectional amplification in a gain-assisted cavity-QED system is investigated.The results demonstrate that unidirectional amplification of this system is induced by the phase difference between the atom-cavity coupling strengths associated with the optical gain and a phase-controlled unidirectional amplifier can be achieved.The optimal parameter conditions for the observation of ideal unidirectional amplification are obtained analytically,and are shown to be dependent on phase,atom-cavity and cavity-cavity coupling strength,and atomic dissipation.In particular,it is found that atomic dissipation is another essential condition for the realization of nonreciprocal amplification other than breaking of the time-reversal symmetry,and our unidirectional amplifier is robust against atom-cavity coupling mismatch.Such unidirectional amplifiers are crucial nonreciprocal devices for controlling photon transmission and may have potential applications in quantum information processing.
文摘If the singularity of the cosmic Big Bang is taken as the origin of the reference coordinate system,the surrounding vacuum in the initial moments of it would exhibit radially-outward right-handed spiral motion at light speed.Based on this spatial motion hypothesis,we derive a unified field equation and a set of Maxwell’s equations for vacuum SWs(Scalar Waves)generating a huge spiral force field that drives the energy to spiral inwardly and distort,leading to the formation of mass.Furthermore,they also uncover that mass is fundamentally an ultimate expression of energy,manifesting as the result of spiral motion of space at light speed.And then,we indirectly validate the theory that coherent light waves’collision generate SWs and subsequently mass through the experiment verifying the Breit-Wheeler process.The establishment of our theory offers a new analytical tool for the exploration of mass origin,the cosmic Big Bang,unified field theories.
文摘QED(quantum electrodynamics)is the QFT(quantum field theory)describing the interaction between light and matter.While conventional QED is based on TEM(transverse electromagnetic)waves,there has been increasing interest in the theoretical and experimental exploration of LSW(longitudinal scalar waves)solutions that are often omitted in CED(classical electrodynamics)but may have physical significance in nontrivial vacuum conditions.This paper delves into the theoretical foundation of LSW,their role in QED,and the associated mathematical equations governing their dynamics.
基金supported by funding provided by Jilin Province(Grant No. 20230101357JC)the National Science Foundation of China (Grant No. 12375010)the Innovation Program for Quantum Science and Technology (Grant No.2023ZD0300700)。
文摘We investigate phase-controlled bound states in a one-dimensional photonic waveguide coupled to an artificial giant atom at two distant sites. Specifically, we identify the bound state out of the continuum(BOC) and the bound state in the continuum(BIC) and derive the exact existence condition for the BOC. Furthermore, we analytically determine the BIC's frequency and photonic distribution profile. Remarkably, our analysis reveals quantum beats in both atomic and photonic dynamics, arising from coherent oscillations between the BIC and BOC. These results establish a novel approach for manipulating waveguide quantum electrodynamics via engineered bound states, with potential applications in quantum information processing.
基金support from the National Key Research and Development Program of China(grant 2020YFA0715000)the National Natural Science Foundation of China(grant 62075111)+2 种基金the Tsinghua University Initiative Scientific Research ProgramH.-B.S.acknowledges support from the National Natural Science Foundation of China(grant 61960206003)Tsinghua-Foshan Innovation Special Fund(grant 2021THFS0102).
文摘Waveguide quantum electrodynamics(QED)system manifests an ideal platform for studying many-body physics.When multiple emitters are coupled to a common waveguide,subradiant states may arise because of the waveguide-mediated interaction,leading to a long lifetime because of their immunity to the waveguide modeinduced dissipation.However,they can still be influenced by local environments,which are incoherent for different emitters and cannot be canceled out through interference.Herein,a new mechanism termed energy quantum confinement effect(EQCE)is proposed in a non-Markovian waveguide QED system to suppress the local dissipation.The energy quantum is confined in the waveguide by emitters,suppressing spontaneous decay of the emitters.The EQCE makes the system partly free from local dissipation of emitters,leading to a total decay rate lower than the local decay rate.We further show that similar effect occurs spontaneously by self-interference and can be stressed by cooperative coupling,relaxing the requirement for initializing the emitters into a remotely entangled state.
