Linear superposition principle is a basic characteristic of quantum mechanics. The quantum interference of matter wave results from this principle. Recently, considerable effort has been devoted to the study of the pr...Linear superposition principle is a basic characteristic of quantum mechanics. The quantum interference of matter wave results from this principle. Recently, considerable effort has been devoted to the study of the properties of superpositions of two or more coherent states, i.e. the Schr(?)dinger cat states.It is shown that the superpositions of coherent states have properties different from those of the coherent state, such as the higher-order squeezing, sub-Poissonian distribution, oscillatory photon statistics and antibunching effect, because of the quantum interference between the components of the cat states. The emergence of these non-classical effects makes the study of the Schr(?)展开更多
We investigate the geometric phase and dynamic phase of a two-level fermionic system with dispersive interaction, driven by a quantized bosonic field which is simultaneously subjected to parametric amplification. It i...We investigate the geometric phase and dynamic phase of a two-level fermionic system with dispersive interaction, driven by a quantized bosonic field which is simultaneously subjected to parametric amplification. It is found that the geometric phase is induced by a counterpart of the Stark shift. This effect is due to distinct shifts in the field frequency induced by interaction between different states （｜e〉 and ｜g〉 ） and cavity field, and a simple geometric interpretation of this phenomenon is given, which is helpful to understand the natural origin of the geometric phase.展开更多
Spontaneous symmetry breaking(SSB)plays a central role in understanding a large variety of phenomena associated with phase transitions,such as superfluid and superconductivity.So far,the transition from a symmetric va...Spontaneous symmetry breaking(SSB)plays a central role in understanding a large variety of phenomena associated with phase transitions,such as superfluid and superconductivity.So far,the transition from a symmetric vacuum to a macroscopically ordered phase has been substantially explored.The process bridging these two distinct phases is critical to understanding how a classical world emerges from a quantum phase transition,but so far remains unexplored in experiment.We here report an experimental demonstration of such a process with a quantum Rabi model engineered with a superconducting circuit.We move the system from the normal phase to the superradiant phase featuring two symmetry-breaking field components,one of which is observed to emerge as the classical reality.The results demonstrate that the environment-induced decoherence plays a critical role in the SSB.展开更多
基金Project partly supported by the National Natural Science Foundation of China.
文摘Linear superposition principle is a basic characteristic of quantum mechanics. The quantum interference of matter wave results from this principle. Recently, considerable effort has been devoted to the study of the properties of superpositions of two or more coherent states, i.e. the Schr(?)dinger cat states.It is shown that the superpositions of coherent states have properties different from those of the coherent state, such as the higher-order squeezing, sub-Poissonian distribution, oscillatory photon statistics and antibunching effect, because of the quantum interference between the components of the cat states. The emergence of these non-classical effects makes the study of the Schr(?)
基金Supported by the National Natural Science Foundation of China under Grant No 10575040.
文摘We investigate the geometric phase and dynamic phase of a two-level fermionic system with dispersive interaction, driven by a quantized bosonic field which is simultaneously subjected to parametric amplification. It is found that the geometric phase is induced by a counterpart of the Stark shift. This effect is due to distinct shifts in the field frequency induced by interaction between different states （｜e〉 and ｜g〉 ） and cavity field, and a simple geometric interpretation of this phenomenon is given, which is helpful to understand the natural origin of the geometric phase.
基金supported by the National Natural Science Foundation of China(Grant Nos.11874114,12274080,and 11875108)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0300200)。
文摘Spontaneous symmetry breaking(SSB)plays a central role in understanding a large variety of phenomena associated with phase transitions,such as superfluid and superconductivity.So far,the transition from a symmetric vacuum to a macroscopically ordered phase has been substantially explored.The process bridging these two distinct phases is critical to understanding how a classical world emerges from a quantum phase transition,but so far remains unexplored in experiment.We here report an experimental demonstration of such a process with a quantum Rabi model engineered with a superconducting circuit.We move the system from the normal phase to the superradiant phase featuring two symmetry-breaking field components,one of which is observed to emerge as the classical reality.The results demonstrate that the environment-induced decoherence plays a critical role in the SSB.
