Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Chinese Physics Letters

Strong Correlation and Anticorrelation via Phase-Dependent Coherent Population Trapping

Yandong Peng, Xiangming Hu, Gong Cheng

Published Feb 1, 2008• 1 citation
Publisher

Abstract

We present the phase control of photon correlations in a driven four-level system in the double lambda configuration. The strong correlation and the anticorrelation are obtained when the collective phase of four applied laser fields is varied. The coherent control is based on the phase-dependent coherent population trapping (CPT). The strong correlation occurs when the system operates near CPT, while the anticorrelation occurs when the system is far away from CPT.

DOI
10.1088/0256-307x/25/2/039

Related papers

Observation of Phase-Dependent Coherent Population Trapping in Optically Closed Atomic Systems

Wolfgang Maichen, Richard Gaggl, Eugeny Korsunsky +1 more

Phase-dependent coherent population trapping (CPT) was observed using a thermal Na atomic beam irradiated by four laser fields derived from two dye lasers. Investigations were made on Λ- and double Λ-systems created in the D 1 line, both with and without magnetic field that lifts degeneracy of the Zeeman sublevels. In all cases a sharp decrease of fluorescence intensity was observed for certain values of the relative phase of the light waves, indicating that the occurrence of CPT depends on this phase. The shape of the phase dependence as well as its behaviour with respect to laser intensity fits well theoretical predictions.

Europhysics Letters (EPL)•Aug 1, 1995•43 citations

Coherent population trapping via quantum interference of incoherent pump processes in three-level systems

Xiangming Hu, Jie-Peng Zhang

Quantum interference has been predicted to occur in a three-level Λ system with near-degenerate dipole allowed transitions, which are coupled to the same linearly polarized incoherent field. For the Λ system with two degenerate lower levels, we show that (a) quantum interference of incoherent pump processes leads to coherent population trapping (CPT), and (b) when two coherent fields are applied to two transitions on two-photon resonance, CPT appears when the amplitudes and phases of the applied coherent fields and the polarization angle of the incoherent field satisfy certain conditions. Further, the physical mechanism and the above conditions for CPT are presented.

Journal of Physics B Atomic Molecular and Optical Physics•Dec 17, 2003•19 citations

Phase-dependent atomic coherence and interference in multi-level atomic systems

Jiepeng Zhang, Yifu Zhu

Atomic coherence and interference manifested by electromagentically induced transparency (EIT) and coherent population trapping (CPT) plays an important role in the current studies of atom-photon interactions and has found numerous applications in optical physics. EIT is created in a three-level atomic system by a coupling field and results in destructive interference between two excitation paths of a weak probe laser interacting with the atomic medium. This leads to suppressed linear absorption and rapidly varying atomic dispersion for the probe laser near the atomic resonance, which provides the platform for a variety of applications such as nonlinear optics at low light levels, slow light manipulation, and quantum state engineering for photons and atoms. Here we extend the simple three-level EIT system to more complicated and versatile configurations in a multi-level atomic system coupled by multiple laser fields. We show that with multiple excitation paths provided by different laser fields, phase-dependent quantum interference is induced: either constructive or destructive interference can be realized by varying the relative phases among the laser fields. Two specific examples are discussed. One is a three-level system coupled by bichromatic coupling and probe fields, in which the phase dependent interference between the resonant two-photon Raman transitions can be initiated and controlled. Another is a four-level system coupled by two coupling fields and two probe fields, in which a double-EIT configuration is created by the phase-dependent interference between three-photon and one-photon excitation processes. We analyze the coherently coupled multi-level atomic system and discuss the control parameters for the onset of constructive or destructive quantum interference. We describe two experiments performed with cold Rb atoms that can be approximately treated as the coherently coupled three-level and four-level atomic systems respectively. The experimental results show the phase-dependent quantum coherence and interference in the multi-level Rb atomic system, and agree with the theoretical calculations based on the coherently coupled three-level or four-level model system.

BENTHAM SCIENCE PUBLISHERS eBooks•Jan 1, 2009•0 citations

Transient coherent population trapping in a closed loop interaction scheme

Wolfgang Maichen, Ferruccio Renzoni, I. E. Mazets +2 more

We investigated the existence of coherent population trapping (CPT) as a transient effect dependent on the rate of change of interaction parameters between an atom and light waves. For that purpose we exploited the phase dependence of CPT in a closed double-\ensuremath{\Lambda} interaction scheme, varying the total phase of the atomic transition loop linearly in time by detuning the light waves from exact four-photon resonance. For a slowly changing phase (that is, for small detunings) we observed the subsequent creation and destruction of CPT depending on the varying phase, while for higher speed of phase change CPT disappears. An analytical solution for a special case for a double-\ensuremath{\Lambda} interaction scheme that can be used to understand the principles of this phenomenon is presented. A qualitative comparison with our experiment shows good agreement within the limits of our theoretical considerations, confirming the validity of the basic idea. \textcopyright{} 1996 The American Physical Society.

Physical Review A•May 1, 1996•54 citations

Coherent Population Trapping Induced by Phase Modulated and Fluctuating Fields

Jian Wang, Xiangming Hu

We examine the effects of cross correlated phase fluctuations on the coherent population trapping (CPT) induced by a pair of phase-modulated fields with equal modulation frequencies in a three-level Λ system. The maximal coherence of -0.5, which appears when CPT occurs for equal modulation indices, is preserved in the presence of the critically cross-correlated fluctuations. Unexpectedly, the non-maximal coherence, which is established when CPT is obtained for different modulation indices, is significantly enhanced due to the critically cross-correlated fluctuations.

Chinese Physics Letters•Jan 18, 2007•2 citations

Entanglement control via coherent population trapping in the closed –loop quantum systems

Firouz Amiri, Zeinab Kordi

In this research, the disentanglement conditions between the coated atom and its spontaneous emission in double- lambda quantum system was investigated. Initially, the entanglement increased due to the interaction between the laser fields and the four- level atom. This entanglement can be controlled by changing the intensity of the applied fields. By applying the two coupling fields, the system is entangled and the system would be disentangled with one coupling field and one probe field. The present research demonstrated that spontaneous emission by changing the population of atoms in the alignments is a good source of entanglement, but fields were manipulated in such a way that this entanglement was reduced by coherent trapping of the population for the atoms.

فصلنامه علمی کارافن•Aug 23, 2021•0 citations
We present the phase control of photon correlations in a driven four-level system in the double lambda configuration. The strong correlation and the anticorrelation are obtained when the collective phase of four applied laser fields is varied. The coherent control is based on the phase-dependent coherent population trapping (CPT). The strong correlation occurs when the system operates near CPT, while the anticorrelation occurs when the system is far away from CPT.
Phase-dependent coherent population trapping (CPT) was observed using a thermal Na atomic beam irradiated by four laser fields derived from two dye lasers. Investigations were made on Λ- and double Λ-systems created in the D 1 line, both with and without magnetic field that lifts degeneracy of the Zeeman sublevels. In all cases a sharp decrease of fluorescence intensity was observed for certain values of the relative phase of the light waves, indicating that the occurrence of CPT depends on this phase. The shape of the phase dependence as well as its behaviour with respect to laser intensity fits well theoretical predictions.
Quantum interference has been predicted to occur in a three-level Λ system with near-degenerate dipole allowed transitions, which are coupled to the same linearly polarized incoherent field. For the Λ system with two degenerate lower levels, we show that (a) quantum interference of incoherent pump processes leads to coherent population trapping (CPT), and (b) when two coherent fields are applied to two transitions on two-photon resonance, CPT appears when the amplitudes and phases of the applied coherent fields and the polarization angle of the incoherent field satisfy certain conditions. Further, the physical mechanism and the above conditions for CPT are presented.
Atomic coherence and interference manifested by electromagentically induced transparency (EIT) and coherent population trapping (CPT) plays an important role in the current studies of atom-photon interactions and has found numerous applications in optical physics. EIT is created in a three-level atomic system by a coupling field and results in destructive interference between two excitation paths of a weak probe laser interacting with the atomic medium. This leads to suppressed linear absorption and rapidly varying atomic dispersion for the probe laser near the atomic resonance, which provides the platform for a variety of applications such as nonlinear optics at low light levels, slow light manipulation, and quantum state engineering for photons and atoms. Here we extend the simple three-level EIT system to more complicated and versatile configurations in a multi-level atomic system coupled by multiple laser fields. We show that with multiple excitation paths provided by different laser fields, phase-dependent quantum interference is induced: either constructive or destructive interference can be realized by varying the relative phases among the laser fields. Two specific examples are discussed. One is a three-level system coupled by bichromatic coupling and probe fields, in which the phase dependent interference between the resonant two-photon Raman transitions can be initiated and controlled. Another is a four-level system coupled by two coupling fields and two probe fields, in which a double-EIT configuration is created by the phase-dependent interference between three-photon and one-photon excitation processes. We analyze the coherently coupled multi-level atomic system and discuss the control parameters for the onset of constructive or destructive quantum interference. We describe two experiments performed with cold Rb atoms that can be approximately treated as the coherently coupled three-level and four-level atomic systems respectively. The experimental results show the phase-dependent quantum coherence and interference in the multi-level Rb atomic system, and agree with the theoretical calculations based on the coherently coupled three-level or four-level model system.
We investigated the existence of coherent population trapping (CPT) as a transient effect dependent on the rate of change of interaction parameters between an atom and light waves. For that purpose we exploited the phase dependence of CPT in a closed double-\ensuremath{\Lambda} interaction scheme, varying the total phase of the atomic transition loop linearly in time by detuning the light waves from exact four-photon resonance. For a slowly changing phase (that is, for small detunings) we observed the subsequent creation and destruction of CPT depending on the varying phase, while for higher speed of phase change CPT disappears. An analytical solution for a special case for a double-\ensuremath{\Lambda} interaction scheme that can be used to understand the principles of this phenomenon is presented. A qualitative comparison with our experiment shows good agreement within the limits of our theoretical considerations, confirming the validity of the basic idea. \textcopyright{} 1996 The American Physical Society.
We examine the effects of cross correlated phase fluctuations on the coherent population trapping (CPT) induced by a pair of phase-modulated fields with equal modulation frequencies in a three-level Λ system. The maximal coherence of -0.5, which appears when CPT occurs for equal modulation indices, is preserved in the presence of the critically cross-correlated fluctuations. Unexpectedly, the non-maximal coherence, which is established when CPT is obtained for different modulation indices, is significantly enhanced due to the critically cross-correlated fluctuations.
In this research, the disentanglement conditions between the coated atom and its spontaneous emission in double- lambda quantum system was investigated. Initially, the entanglement increased due to the interaction between the laser fields and the four- level atom. This entanglement can be controlled by changing the intensity of the applied fields. By applying the two coupling fields, the system is entangled and the system would be disentangled with one coupling field and one probe field. The present research demonstrated that spontaneous emission by changing the population of atoms in the alignments is a good source of entanglement, but fields were manipulated in such a way that this entanglement was reduced by coherent trapping of the population for the atoms.