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

Optics and Spectroscopy

Effect of the spatial inhomogeneity of a field in a micromaser experiment with the selective measurement of atomic states

A. V. Kozlovskiĭ

Published Apr 1, 2007• 3 citations
Publisher

Abstract

It is shown that the theoretical analysis of a micromaser experiment with the selective measurement of atomic states is impossible without consideration of the spatial structure of the field and of the statistical spread of the atomic velocities in the cavity. An approximate theory, ignoring the dynamic effects associated with the mentioned factors, yields not only quantitatively, but also qualitatively different theoretical predictions. The dynamics of the field and the mean number of photons in the trapping states realized in this case differ significantly from the predictions of the idealized standard theory used at present. Along with the process of establishment of the stationary Fock state of the field, under certain conditions, it appears possible to form the quasistationary quantum state of the field with large fluctuations of the number of photons, accompanied by the exit of the field from the cavity (“quasi-dissipation”), and the following stepwise transition into the state of the electromagnetic vacuum. It is shown that, under the conditions of the micromaser experiment, the information about the states of atoms, passed through the cavity, in the case considered, does not allow one to draw an unambiguous conclusion about the state of the field in the cavity.

DOI
10.1134/s0030400x07040157

Related papers

Field states upon micromaser dispersive quantum nondemolition measurement of the number of photons

A. V. Kozlovskiĭ

Dispersive quantum nondemolition measurement of the number of photons is analyzed in the micromaser scheme. It has been shown that the stationary Fock state of the field in a cavity that is considered as the result of quantum nondemolition measurement is realized only in a particular case for strictly determined parameters of the system, and small variation in one of the parameters of the system results in a qualitative change in the field state. In the general case, the field state is characterized by large fluctuations of the number of photons and the mean number of photons, which are very sensitive to the parameters of the system. It has been shown that the detection of the Ramsey interference pattern is possible only when the sequence of atoms passing through the cavity is highly monokinetic.

Journal of Experimental and Theoretical Physics Letters•Dec 1, 2005•1 citation

Trapping States in the Micromaser

M. Weidinger, Benjamin T. H. Varcoe, R. Heerlein +1 more

Trapping states in the one-atom maser or micromaser are predicted by maser theory and are a direct consequence of the quantization of the electromagnetic field. They have been found in our experiment when the inversion of atoms leaving the cavity is observed while the interaction time is scanned. They correspond to quantum states of the atom-cavity system and under certain conditions represent Fock states. The trapping states occur when the atom-field dynamics complete a full evolution (or multiples thereof). Owing to feedback through the maser dynamics, a stabilization of the photon number in the steady state field of the maser cavity is achieved.

Physical Review Letters•May 10, 1999•251 citations

Decay of number-state superpositions in a micromaser

John J. Slosser, T. A. B. Kennedy, Pierre Meystre

Coherent superpositions of quantum states are very sensitive to coupling to the environment. The fluctuations associated with this coupling tend to wash out quantum phases, so that in practice only quantum mixtures are observed at the macroscopic level. This problem has been the object of recent interest in connection with measurement theory (Schrodinger cat). Theoretical predictions indicate that the decay of quantum coherences in the so-called pointer basis is amplified by a factor proportional to a measure of the distance in Hilbert space between the states. Micromasers offer a possible experimental tool to investigate the decay of such coherences. Theoretical studies of a lossless version of the micromaster have shown the existence of trapping states | n q 〉 of the cavity mode. These number states are such that atoms injected in the upper state into the cavity experience a 2qπ interaction with the field. Cavity states of the form | ψ 〉 = Σ q C q | n q 〉 are easily shown to be dynamic steady states of the system. Number states are not a pointer basis for the micromaser, and our theoretical results will evidence the qualitative difference in the nature of coherence decay between this and previously studied cases. Because the decay times of micromaser cavities are typically of the order of hundreds of milliseconds, our results should be amenable to experimental verification.

Annual Meeting Optical Society of America•Jan 1, 1988•0 citations

Quantum revivals in micromasers

Ewan M. Wright, P. Meystre

A distinctive signature of the granulated nature of the electromagnetic field is the revivals known to occur in the dynamics of a two-level atom interacting with a single-field mode (Jaynes-Cummings model). The development of high-Q single-mode cavities combined with progress in Rydberg atom spectroscopy has led to a possibility of verifying these predictions. Revival experiments using micromasers have been performed by Walther et al. Here the cavity mode is first allowed to reach a steady state, and then probe atoms are injected into the resonator. By measuring their state as they exit the cavity, one can infer the state of the field. We show that the micromaser experiences Jaynes-Cummingslike revivals when the pump parameter θ is varied. However, in contrast to the conventional Jaynes-Cummings situation, which considers initially coherent fields, the micromaser photon statistics are usually not Poissonian and depend sensitively on θ. The micromaser revivals cannot be explained by a semiclassical theory or linearized quantum fluctuations about the semiclassical solution. Rather, an exact quantum treatment, considering fully the granularity of the cavity mode, is required.

Annual Meeting Optical Society of America•Jan 1, 1988•0 citations

Quantum theory of the micromaser with ultracold three-level atoms interacting with a bimodal cavity field: spatial variation along the cavity axis

Mahmoud Abdel‐Aty, A.‐S. F. Obada

The analytical form of the emission probability produced by the interaction of an ultracold three-level atom with an electromagnetic bimodal cavity field with multi-photon transitions of the atoms (multi-photon mazer) is analysed in the framework of the dressed-state formalism, but is distinguished from other treatments by the inclusion of the spatial variation along the cavity axis. In particular, the cavity field mode profile is considered by using the mesa-mode function and differences in the collapse–revival patterns are reported. We demonstrate that, when propagation effects are taken into consideration, the emission probability is influenced significantly. We provide the necessary arguments to justify the validity of our conclusions for emission probability and the micromaser, whose dynamics are governed by the wavefunction. Our main conclusion is that, in the present system, the inclusion of the spatial dependence is necessary and important. The numerical illustrations provide evidence that, in cases of physical interest, the emission probability can be significant and can be reliably estimated for a broad range of field parameters using the present formalism.

Journal of Physics B Atomic Molecular and Optical Physics•Jul 10, 2003•3 citations

Dynamics and quasi-stationary states of N-atom micromaser

George P. Miroshnichenko, Andrei V. Rybin, JUSSI TIMONEN +1 more

Summary form only given. We consider a N-atom micromaser model described by a hamiltonian. Taking into account field relaxation between consecutive N-atom packets we study dynamics and quasi-stationary states of subsystems in the model. Experimentally, such a system may be realized on a high-density atom flux prepared with help of ultrashort time pulses of exciting laser, in order to achieve small packets and avoid large dispersion of entrance times. For initially diagonal density operator of atoms, the system dynamics and particularly of the field reduced density matrix (RDM) have significant simplification, called diagonal invariance. Under such conditions it was found that the field dynamics might be divided into two stages, a rapid stage and a quasi-stationary stage. This behavior is determined by quasi-trapped states, which are a generalization of well known trapped states in the one-atom micromaser. We want to emphasize that our work raises important questions on a possibility to apply formalism of density matrix for description of such experiments.

Conference on Lasers and Electro-Optics•Aug 29, 2005•0 citations
It is shown that the theoretical analysis of a micromaser experiment with the selective measurement of atomic states is impossible without consideration of the spatial structure of the field and of the statistical spread of the atomic velocities in the cavity. An approximate theory, ignoring the dynamic effects associated with the mentioned factors, yields not only quantitatively, but also qualitatively different theoretical predictions. The dynamics of the field and the mean number of photons in the trapping states realized in this case differ significantly from the predictions of the idealized standard theory used at present. Along with the process of establishment of the stationary Fock state of the field, under certain conditions, it appears possible to form the quasistationary quantum state of the field with large fluctuations of the number of photons, accompanied by the exit of the field from the cavity (“quasi-dissipation”), and the following stepwise transition into the state of the electromagnetic vacuum. It is shown that, under the conditions of the micromaser experiment, the information about the states of atoms, passed through the cavity, in the case considered, does not allow one to draw an unambiguous conclusion about the state of the field in the cavity.
Dispersive quantum nondemolition measurement of the number of photons is analyzed in the micromaser scheme. It has been shown that the stationary Fock state of the field in a cavity that is considered as the result of quantum nondemolition measurement is realized only in a particular case for strictly determined parameters of the system, and small variation in one of the parameters of the system results in a qualitative change in the field state. In the general case, the field state is characterized by large fluctuations of the number of photons and the mean number of photons, which are very sensitive to the parameters of the system. It has been shown that the detection of the Ramsey interference pattern is possible only when the sequence of atoms passing through the cavity is highly monokinetic.
Trapping states in the one-atom maser or micromaser are predicted by maser theory and are a direct consequence of the quantization of the electromagnetic field. They have been found in our experiment when the inversion of atoms leaving the cavity is observed while the interaction time is scanned. They correspond to quantum states of the atom-cavity system and under certain conditions represent Fock states. The trapping states occur when the atom-field dynamics complete a full evolution (or multiples thereof). Owing to feedback through the maser dynamics, a stabilization of the photon number in the steady state field of the maser cavity is achieved.
Coherent superpositions of quantum states are very sensitive to coupling to the environment. The fluctuations associated with this coupling tend to wash out quantum phases, so that in practice only quantum mixtures are observed at the macroscopic level. This problem has been the object of recent interest in connection with measurement theory (Schrodinger cat). Theoretical predictions indicate that the decay of quantum coherences in the so-called pointer basis is amplified by a factor proportional to a measure of the distance in Hilbert space between the states. Micromasers offer a possible experimental tool to investigate the decay of such coherences. Theoretical studies of a lossless version of the micromaster have shown the existence of trapping states | n q 〉 of the cavity mode. These number states are such that atoms injected in the upper state into the cavity experience a 2qπ interaction with the field. Cavity states of the form | ψ 〉 = Σ q C q | n q 〉 are easily shown to be dynamic steady states of the system. Number states are not a pointer basis for the micromaser, and our theoretical results will evidence the qualitative difference in the nature of coherence decay between this and previously studied cases. Because the decay times of micromaser cavities are typically of the order of hundreds of milliseconds, our results should be amenable to experimental verification.
A distinctive signature of the granulated nature of the electromagnetic field is the revivals known to occur in the dynamics of a two-level atom interacting with a single-field mode (Jaynes-Cummings model). The development of high-Q single-mode cavities combined with progress in Rydberg atom spectroscopy has led to a possibility of verifying these predictions. Revival experiments using micromasers have been performed by Walther et al. Here the cavity mode is first allowed to reach a steady state, and then probe atoms are injected into the resonator. By measuring their state as they exit the cavity, one can infer the state of the field. We show that the micromaser experiences Jaynes-Cummingslike revivals when the pump parameter θ is varied. However, in contrast to the conventional Jaynes-Cummings situation, which considers initially coherent fields, the micromaser photon statistics are usually not Poissonian and depend sensitively on θ. The micromaser revivals cannot be explained by a semiclassical theory or linearized quantum fluctuations about the semiclassical solution. Rather, an exact quantum treatment, considering fully the granularity of the cavity mode, is required.
The analytical form of the emission probability produced by the interaction of an ultracold three-level atom with an electromagnetic bimodal cavity field with multi-photon transitions of the atoms (multi-photon mazer) is analysed in the framework of the dressed-state formalism, but is distinguished from other treatments by the inclusion of the spatial variation along the cavity axis. In particular, the cavity field mode profile is considered by using the mesa-mode function and differences in the collapse–revival patterns are reported. We demonstrate that, when propagation effects are taken into consideration, the emission probability is influenced significantly. We provide the necessary arguments to justify the validity of our conclusions for emission probability and the micromaser, whose dynamics are governed by the wavefunction. Our main conclusion is that, in the present system, the inclusion of the spatial dependence is necessary and important. The numerical illustrations provide evidence that, in cases of physical interest, the emission probability can be significant and can be reliably estimated for a broad range of field parameters using the present formalism.
Summary form only given. We consider a N-atom micromaser model described by a hamiltonian. Taking into account field relaxation between consecutive N-atom packets we study dynamics and quasi-stationary states of subsystems in the model. Experimentally, such a system may be realized on a high-density atom flux prepared with help of ultrashort time pulses of exciting laser, in order to achieve small packets and avoid large dispersion of entrance times. For initially diagonal density operator of atoms, the system dynamics and particularly of the field reduced density matrix (RDM) have significant simplification, called diagonal invariance. Under such conditions it was found that the field dynamics might be divided into two stages, a rapid stage and a quasi-stationary stage. This behavior is determined by quasi-trapped states, which are a generalization of well known trapped states in the one-atom micromaser. We want to emphasize that our work raises important questions on a possibility to apply formalism of density matrix for description of such experiments.