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

Advances in atomic, molecular, and optical physics

Cavity Quantum Electrod Ynamics

E. A. Hinds

Published Jan 1, 1990• 157 citations
Publisher

Abstract

This chapter focuses on cavity quantum electrodynamics. It presents the modifications of the spontaneous radiation rate in a cavity and the shifts of energy levels. The chapter focuses on experimental work, with an outline of a theoretical framework in which the experiments may be understood. In the laboratory, the study of atoms in cavities is a relatively young field in which much of the effort is still aimed at elucidating the basic physical principles at work and demonstrating the elementary modifications of energies and the rates of an atom in a cavity. However, the ability to adjust the electromagnetic spectrum of the vacuum is leading into a remarkable new domain of quantum physics in which atoms can decay from the ground state to an excited state, radiative corrections can be far larger than fine structure, and electromagnetic fields can be prepared with an exact number of photons. This realm of physics is now known as “cavity quantum electrodynamics.”

DOI
10.1016/s1049-250x(08)60201-3

Related papers

Cavity quantum electrodynamics

HERBERT WALTHER, Benjamin T. H. Varcoe, Berthold‐Georg Englert +1 more

This paper reviews the work on cavity quantum electrodynamics of free atoms. In recent years, cavity experiments have also been conducted on a variety of solid-state systems resulting in many interesting applications, of which microlasers, photon bandgap structures and quantum dot structures in cavities are outstanding examples. Although these phenomena and systems are very interesting, discussion is limited here to free atoms and mostly single atoms because these systems exhibit clean quantum phenomena and are not disturbed by a variety of other effects. At the centre of our review is the work on the one-atom maser, but we also give a survey of the entire field, using free atoms in order to show the large variety of problems dealt with. The cavity interaction can be separated into two main regimes: the weak coupling in cavity or cavity-like structures with low quality factors Q and the strong coupling when high- Q cavities are involved. The weak coupling leads to modification of spontaneous transitions and level shifts, whereas the strong coupling enables one to observe a periodic exchange of photons between atoms and the radiation field. In this case, atoms and photons are entangled, this being the basis for a variety of phenomena observed, some of them leading to interesting applications in quantum information processing. The cavity experiments with free atoms reached a new domain with the advent of experiments in the visible spectral region. A review on recent achievements in this area is also given.

Reports on Progress in Physics•Apr 3, 2006•1,198 citations

Manipulating molecules with quantum light

Markus Kowalewski, Shaul Mukamel

It was first realized by Purcell (1) that the spontaneous emission rate of a quantum system can be enhanced or suppressed by placing it in a resonant radiofrequency cavity. Spontaneous emission as it was first theoretically described by Einstein (2) is not a pure property of matter. It is described by matter coupled to quantized radiation field modes, which can be manipulated in an artificial structure such as a cavity. Cavity quantum electrodynamics (QED) is used to describe such effects that intimately depend on the fact that light is made of photons. Cavity QED has been extensively studied in atoms and the experimental proof was awarded with the Nobel Prize in 2012 (3). It has been applied to cooling of single atoms and for the detection of single atoms and creating and studying states with few photons and few atoms (4). In more recent developments these ideas have been extended to manipulate electronic states (5) and vibrations in molecules (6, 7). In PNAS, Flick et al. (8) introduce recent theoretical developments for the application of cavity QED to molecules and suggest possible novel applications to photochemistry. These include nonadiabatic dynamics of molecules in cavities, the modification of molecular properties, and the integration of QED with density functional theory. A quantized electromagnetic field mode can be described as a harmonic oscillator whose coordinate is the electric field displacement (Fig. 1 A ). The zero point energy translates into a nonvanishing field intensity ⟨ e 2 ⟩ in the ground state | 0 ⟩ (vacuum fluctuations). The electric vacuum field increases for a small cavity volume e c = ℏ ω c V ϵ 0 , [1] Fig. 1. ( A ) Illustration of the standing wave cavity mode and the resulting field quantization (Fock states). ( B ) Combined matter-field states (dressed states, | ± , n ⟩ … [↵][1]1To whom correspondence should be addressed. Email: smukamel{at}uci.edu. [1]: #xref-corresp-1-1

Proceedings of the National Academy of Sciences•Mar 16, 2017•63 citations

Cavity quantum electrodynamics

Partha Ghose

Introduction Ever since 1916/17 when Einstein argued [45] [46] that spontaneous emission must occur if matter and radiation are to achieve thermal equilibrium, physicists have believed that spontaneous emission is an inherent quantum mechanical property of atoms and that excited atoms inevitably radiate. This view, however, overlooks the fact that spontaneous emission is a consequence of the coupling of quantized energy states of atoms with the quantized radiation field, and is a manifestation of quantum noise or of emission ‘stimulated’ by ‘vacuum fluctuations’. An infinity of vacuum states is available to the photon radiated by an excited atom placed in free space, leading to the effective irreversibility of such emissions. If these vacuum states are modified, as for example by placing an excited atom between closely spaced mirrors or in a small cavity (essentially the Casimir effect), spontaneous emission can be greatly inhibited or enhanced or even made reversible. Recent advances in atomic and optical techniques have made it possible to control and manipulate spontaneous emission. A whole new branch of quantum optics called ‘cavity QED’ has developed since 1987 utilizing these dramatic changes in spontaneous emission rates in cavities to construct new kinds of microscopic masers or micromasers that operate with a single atom and a few photons or with photons emitted in pairs in a two-photon transition.

Cambridge University Press eBooks•Apr 29, 1999•0 citations

Rydberg Atoms and Radiation in Cavities–Quantum and Collective Effects

S. Haroche, P. Goy, M. Groß +1 more

Rydberg atoms excited in microwave resonators are ideal systems to test quantum electrodynamics on an unusual scale.1 Owing to their very large electric dipole sizes, these atoms are indeed coupled so strongly to infrared and millimeter-wave radiation that the field of a few photons—ultimately the one of a single photon—stored in a cavity is large enough to induce important transition rates during the atomic time of flight across the cavity. As a result quantum radiative effects are observed in a range of frequencies where usual atomic systems behave as purely classical radiators. The enhancement of the spontaneous emission rate of a single atom prepared in a tuned cavity has already been observed.2 For a resonant cavity with very small losses, a point should be reached where the atom can no longer decay but instead reversibly oscillates between the two states involved in the transition resonant with the cavity mode. Experiments aimed at the observation of this new regime of quantum electrodynamics evolution are under way

•Jun 18, 1984•1 citation

Cavity Quantum Electrodynamics

M. Brune, S. Haroche

Cavity qed is the domain of quantum optics which studies the behaviour of single atoms and photons coupled together in an electromagnetic resonator. During the last ten years, various spectacular effects have been observed on such systems, either on the atom’s or on the field’s properties. The presence of a cavity around an atom can produce an alteration of the atomic radiative rates which has been observed in several experiments. Ideally, cavity qed deals with two-level atoms coupled resonantly or nearly resonantly to a single cavity mode. This is of course a simplification of real situations, in which atoms have many levels and the cavity sustains more than one mode. The amplitudes associated to the upper and lower atomic states oscillate as a function of time, revealing the ‘vacuum Rabi oscillation’ effect. The amplitudes associated to the upper and lower atomic states oscillate as a function of time, revealing the ‘vacuum Rabi oscillation’ effect.

CRC Press eBooks•Dec 12, 2020•17 citations

Nonperturbative atom-photon interactions in an optical cavity

H. J. Carmichael, L. Tian, Wei Ren

One of the principal developments in cavity quantum electrodynamics in the last few years has been the extension of the ideas originally applied to systems of Rydberg atoms in microwave cavities to optical frequencies. As a corollary of this, more attention is being paid to quantum fluctuations and photon statistics. Another development, still in its infancy, is a move toward experiments using slowed or trapped atoms, or velocity selected beams; these methods are needed to enter the nonperturbative (strong dipole coupling) regime for one atom where there are experiments on subtle quantum-statistical effects go carry out. In this chapter we solve a number of theoretical problems related to these themes. Although the focus of the work is on optical systems, most of what we do is also relevant at microwave frequencies. We emphasize quantum fluctuations and photon statistics, and we try always to separate the quantum physics from those aspects of the physics that are understandable in classical terms. On the whole we only pay attention to the nonperturbative regime of cavity quantum electrodynamics where the dipole coupling strength is larger than the dissipation rates. 59 refs., 14 figs.

•Dec 31, 1994•4 citations
This chapter focuses on cavity quantum electrodynamics. It presents the modifications of the spontaneous radiation rate in a cavity and the shifts of energy levels. The chapter focuses on experimental work, with an outline of a theoretical framework in which the experiments may be understood. In the laboratory, the study of atoms in cavities is a relatively young field in which much of the effort is still aimed at elucidating the basic physical principles at work and demonstrating the elementary modifications of energies and the rates of an atom in a cavity. However, the ability to adjust the electromagnetic spectrum of the vacuum is leading into a remarkable new domain of quantum physics in which atoms can decay from the ground state to an excited state, radiative corrections can be far larger than fine structure, and electromagnetic fields can be prepared with an exact number of photons. This realm of physics is now known as “cavity quantum electrodynamics.”
This paper reviews the work on cavity quantum electrodynamics of free atoms. In recent years, cavity experiments have also been conducted on a variety of solid-state systems resulting in many interesting applications, of which microlasers, photon bandgap structures and quantum dot structures in cavities are outstanding examples. Although these phenomena and systems are very interesting, discussion is limited here to free atoms and mostly single atoms because these systems exhibit clean quantum phenomena and are not disturbed by a variety of other effects. At the centre of our review is the work on the one-atom maser, but we also give a survey of the entire field, using free atoms in order to show the large variety of problems dealt with. The cavity interaction can be separated into two main regimes: the weak coupling in cavity or cavity-like structures with low quality factors Q and the strong coupling when high- Q cavities are involved. The weak coupling leads to modification of spontaneous transitions and level shifts, whereas the strong coupling enables one to observe a periodic exchange of photons between atoms and the radiation field. In this case, atoms and photons are entangled, this being the basis for a variety of phenomena observed, some of them leading to interesting applications in quantum information processing. The cavity experiments with free atoms reached a new domain with the advent of experiments in the visible spectral region. A review on recent achievements in this area is also given.
It was first realized by Purcell (1) that the spontaneous emission rate of a quantum system can be enhanced or suppressed by placing it in a resonant radiofrequency cavity. Spontaneous emission as it was first theoretically described by Einstein (2) is not a pure property of matter. It is described by matter coupled to quantized radiation field modes, which can be manipulated in an artificial structure such as a cavity. Cavity quantum electrodynamics (QED) is used to describe such effects that intimately depend on the fact that light is made of photons. Cavity QED has been extensively studied in atoms and the experimental proof was awarded with the Nobel Prize in 2012 (3). It has been applied to cooling of single atoms and for the detection of single atoms and creating and studying states with few photons and few atoms (4). In more recent developments these ideas have been extended to manipulate electronic states (5) and vibrations in molecules (6, 7). In PNAS, Flick et al. (8) introduce recent theoretical developments for the application of cavity QED to molecules and suggest possible novel applications to photochemistry. These include nonadiabatic dynamics of molecules in cavities, the modification of molecular properties, and the integration of QED with density functional theory. A quantized electromagnetic field mode can be described as a harmonic oscillator whose coordinate is the electric field displacement (Fig. 1 A ). The zero point energy translates into a nonvanishing field intensity ⟨ e 2 ⟩ in the ground state | 0 ⟩ (vacuum fluctuations). The electric vacuum field increases for a small cavity volume e c = ℏ ω c V ϵ 0 , [1] Fig. 1. ( A ) Illustration of the standing wave cavity mode and the resulting field quantization (Fock states). ( B ) Combined matter-field states (dressed states, | ± , n ⟩ … [↵][1]1To whom correspondence should be addressed. Email: smukamel{at}uci.edu. [1]: #xref-corresp-1-1
Introduction Ever since 1916/17 when Einstein argued [45] [46] that spontaneous emission must occur if matter and radiation are to achieve thermal equilibrium, physicists have believed that spontaneous emission is an inherent quantum mechanical property of atoms and that excited atoms inevitably radiate. This view, however, overlooks the fact that spontaneous emission is a consequence of the coupling of quantized energy states of atoms with the quantized radiation field, and is a manifestation of quantum noise or of emission ‘stimulated’ by ‘vacuum fluctuations’. An infinity of vacuum states is available to the photon radiated by an excited atom placed in free space, leading to the effective irreversibility of such emissions. If these vacuum states are modified, as for example by placing an excited atom between closely spaced mirrors or in a small cavity (essentially the Casimir effect), spontaneous emission can be greatly inhibited or enhanced or even made reversible. Recent advances in atomic and optical techniques have made it possible to control and manipulate spontaneous emission. A whole new branch of quantum optics called ‘cavity QED’ has developed since 1987 utilizing these dramatic changes in spontaneous emission rates in cavities to construct new kinds of microscopic masers or micromasers that operate with a single atom and a few photons or with photons emitted in pairs in a two-photon transition.
Rydberg atoms excited in microwave resonators are ideal systems to test quantum electrodynamics on an unusual scale.1 Owing to their very large electric dipole sizes, these atoms are indeed coupled so strongly to infrared and millimeter-wave radiation that the field of a few photons—ultimately the one of a single photon—stored in a cavity is large enough to induce important transition rates during the atomic time of flight across the cavity. As a result quantum radiative effects are observed in a range of frequencies where usual atomic systems behave as purely classical radiators. The enhancement of the spontaneous emission rate of a single atom prepared in a tuned cavity has already been observed.2 For a resonant cavity with very small losses, a point should be reached where the atom can no longer decay but instead reversibly oscillates between the two states involved in the transition resonant with the cavity mode. Experiments aimed at the observation of this new regime of quantum electrodynamics evolution are under way
Cavity qed is the domain of quantum optics which studies the behaviour of single atoms and photons coupled together in an electromagnetic resonator. During the last ten years, various spectacular effects have been observed on such systems, either on the atom’s or on the field’s properties. The presence of a cavity around an atom can produce an alteration of the atomic radiative rates which has been observed in several experiments. Ideally, cavity qed deals with two-level atoms coupled resonantly or nearly resonantly to a single cavity mode. This is of course a simplification of real situations, in which atoms have many levels and the cavity sustains more than one mode. The amplitudes associated to the upper and lower atomic states oscillate as a function of time, revealing the ‘vacuum Rabi oscillation’ effect. The amplitudes associated to the upper and lower atomic states oscillate as a function of time, revealing the ‘vacuum Rabi oscillation’ effect.
One of the principal developments in cavity quantum electrodynamics in the last few years has been the extension of the ideas originally applied to systems of Rydberg atoms in microwave cavities to optical frequencies. As a corollary of this, more attention is being paid to quantum fluctuations and photon statistics. Another development, still in its infancy, is a move toward experiments using slowed or trapped atoms, or velocity selected beams; these methods are needed to enter the nonperturbative (strong dipole coupling) regime for one atom where there are experiments on subtle quantum-statistical effects go carry out. In this chapter we solve a number of theoretical problems related to these themes. Although the focus of the work is on optical systems, most of what we do is also relevant at microwave frequencies. We emphasize quantum fluctuations and photon statistics, and we try always to separate the quantum physics from those aspects of the physics that are understandable in classical terms. On the whole we only pay attention to the nonperturbative regime of cavity quantum electrodynamics where the dipole coupling strength is larger than the dissipation rates. 59 refs., 14 figs.