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

arXiv:1711.00288

Spontaneous decay in arbitrary cavity size

G. Flores-Hidalgo, M. M. Silva, Onofre Rojas

Published Nov 1, 2017• 0 citations
arXivHTMLPDF

Abstract

We consider a complete study of the influence of the cavity size on the spontaneous decay of an atom excited state, roughly approximated by a harmonic oscillator. We confine the oscillator-field system in a spherical cavity of radius $R$, perfectly reflective, and work in the formalism of dressed coordinates and states, which allows to perform non-perturbative calculations for the probability of the atom to decay spontaneously from the first excited state to the ground state. In free space, $R\to\infty$, we obtain known exact results an for sufficiently small $R$ we have developed a power expansion calculation in this parameter. Furthermore, for arbitrary cavity size radius, we developed numerical computations and showed complete agreement with the exact one for $R\to\infty$ and the power expansion results for small cavities, in this way showing the robustness of our results. We have found that in general the spontaneous decay of an excited state of the atom increases with the cavity size radius and vice versa. For sufficiently small cavities the atom practically does not suffers spontaneous decay, whereas for large cavities the spontaneous decay approaches the free-space $R\to\infty$ value. On the other hand, for some particular values of the cavity radius, in which the cavity is in resonance with the natural frequency of the atom, the spontaneous decay transition probability is increased compared to the free-space case. Finally, we showed how the probability spontaneous decay go from an oscillatory time behaviour, for finite cavity radius, to an almost exponential decay, for free space.

DOI
10.48550/arxiv.1711.00288

Related papers

Non Perturbative Approach to the Time Evolution of a Simple Excited Coupled Quantum System in a Cavity

Adolfo P. C. Malbouisson

We consider a system modeled by a harmonic oscillator of frequency , coupled to the scalar potential inside a reflecting sphere of radius R. We use dressed states introduced originally in [1] and recently employed in [2] to present a non-perturbative unified description of the decay process of the system, in free space and in the case of the system being confined in a finite cavity. In the situation that we start from the initial condition that the system is in the first excited state, we give exact formulas to describe its time evolution for a cavity of arbitrary size. In the particular case of a very large cavity (free space), we recover the behaviour expected from perturbation theory in the limit of the small coupling constant. In the case of a very small cavity, our results are in good agreement with experimental observations

Journal of Applied Mathematics and Physics•Jan 1, 2022•1 citation

Stability of excited atoms in small cavities

G. Flores-Hidalgo, Adolfo P. C. Malbouisson, Y. W. Milla

We consider a system consisting of an atom in the approximation of a harmonic oscillator of frequency $\overline{\ensuremath{\omega}},$ coupled to the scalar potential inside a spherical reflecting cavity of radius R. We use dressed states introduced in a previous publication [Andion, Malbouisson, and Mattos Neto, J. Phys. A 34, 3735 (2001)], which allow a nonperturbative unified description of the atom radiation process, in both cases, of a finite or an arbitrarily large cavity. We perform a study of the energy distribution in a small cavity, with the initial condition that the atom is in the first excited state and we conclude for the quasi-stability of the excited atom. For instance, for a frequency $\overline{\ensuremath{\omega}}$ of the order $\overline{\ensuremath{\omega}}\ensuremath{\sim}4.00\ifmmode\times\else\texttimes\fi{}{10}^{14}/\mathrm{s}$ (in the visible red), starting from the initial condition that the atom is in the first excited level, we find that for a cavity with diameter $2R\ensuremath{\sim}1.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6} \mathrm{m},$ the probability of the atom being at any time still in the first excited level, will be of the order of 97%. For a typical microwave frequency $\overline{\ensuremath{\omega}}\ensuremath{\sim}2.00\ifmmode\times\else\texttimes\fi{}{10}^{10}/\mathrm{s}$ we find stability in the first excited state also of the order of 97% for a cavity radius $R\ensuremath{\sim}1.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2} \mathrm{m}.$

arXiv:physics/0111042•Physical Review A•Jun 20, 2002•20 citations

Spontaneous decay in the presence of dispersing and absorbing bodies: General theory and application to a spherical cavity

Ho Trung Dung, L. Knöll, Dirk‐Gunnar Welsch

A formalism for studying spontaneous decay of an excited two-level atom in the presence of dispersing and absorbing dielectric bodies is developed. An integral equation, which is suitable for numerical solution, is derived for the atomic upper-state-probability amplitude. The emission pattern and the power spectrum of the emitted light are expressed in terms of the Green tensor of the dielectric-matter formation, including absorption and dispersion. The theory is applied to the spontaneous decay of an excited atom at the center of a three-layered spherical cavity, with the cavity wall being modeled by a band-gap dielectric of Lorentz type. Both weak and strong coupling are studied, the latter with a special emphasis on cases where the atomic transition is (i) in the normal-dispersion zone near the medium resonance, and (ii) in the anomalous-dispersion zone associated with the band gap. In a single-resonance approximation, conditions of the appearance of Rabi oscillations and closed solutions to the evolution of the atomic state population are derived, which are in good agreement with the exact numerical results.

arXiv:quant-ph/0003138•Physical Review A•Oct 12, 2000•269 citations

Time evolution of quantum systems in microcavities and in free space -- a non-perturbative approach

G. Flores-Hidalgo, Adolfo P. C. Malbouisson

We consider a system consisting of a particle in the harmonic approximation, having frequency $\barω$, coupled to a scalar field inside a spherical reflecting cavity of diameter $L$. By introducing {\it dressed} coordinates we define {\it dressed} states which allow a non-perturbative unified description of the radiation process, for weak and strong coupling regimes. We perform a study of the energy distribution in a small cavity, with the initial condition that the particle is in the first excited state. In the {\it weak} coupling regime, we conclude for the quasi-stability of the excited particle. For instance, for a frequency $\barω$ of the order $\barω\sim 4.00\times 10^{14}/s$ (in the visible red), starting from the initial condition that the particle is in the first excited level, we find that for a cavity with diameter $L\sim 1.0\times 10^{-6}m$, the probability that the particle be at any time still in the first excited level, will be of the order of 97%. For appropriate cavity dimensions, which are of the same order of those ensuring stability for weak coupling, we ensure for strong coupling the complete decay of the particle to the ground state in a small ellapsed time. Also we consider briefly the effects of a quartic interaction up to first order in the interaction parameter $λ$. We obtain for a large cavity an explicit $λ$-dependent expression for the particle radiation process. This formula is obtained in terms of the corresponding exact expression for the linear case and we conclude for the enhancement of the particle decay induced by the quartic interaction.

arXiv:hep-th/0308198•Aug 28, 2003•1 citation

Thermal effects on the stability of excited atoms in cavities

F. C. Khanna, Adolfo P. C. Malbouisson, J. M. C. Malbouisson +1 more

An atom, coupled linearly to an environment, is considered in a harmonic approximation in thermal equilibrium inside a cavity. The environment is modeled by an infinite set of harmonic oscillators. We employ the notion of dressed states to investigate the time evolution of the atom initially in the first excited level. In a very large cavity (free space) for a long elapsed time, the atom decays and the value of its occupation number is the physically expected one at a given temperature. For a small cavity the excited atom never completely decays and the stability rate depends on temperature.

arXiv:0910.2930•Physical Review A•Mar 22, 2010•6 citations

The effect of a non-zero spontaneous decay rate on teleportation

Grzegorz Chimczak, R. Tanaś

We discuss the influence of the spontaneous decay rate of the excited state on teleportation of the atomic state via cavity decay in the scheme of Bose et al (Bose S, Knight P L, Plenio M B and Vedral V 1999 Phys. Rev. Lett. 83 5158). We show that even a small but non-zero decay rate of the excited state leads to significant effects such as lowering the probability of successful teleportation if the product of the saturation parameter and the spontaneous decay rate is not negligible in comparison with the cavity mode decay rate. We compare analytical results obtained using adiabatic elimination with the results calculated numerically.

Journal of Optics B Quantum and Semiclassical Optics•Nov 4, 2002•11 citations
We consider a complete study of the influence of the cavity size on the spontaneous decay of an atom excited state, roughly approximated by a harmonic oscillator. We confine the oscillator-field system in a spherical cavity of radius RRR, perfectly reflective, and work in the formalism of dressed coordinates and states, which allows to perform non-perturbative calculations for the probability of the atom to decay spontaneously from the first excited state to the ground state. In free space, R→∞R\to\inftyR→∞, we obtain known exact results an for sufficiently small RRR we have developed a power expansion calculation in this parameter. Furthermore, for arbitrary cavity size radius, we developed numerical computations and showed complete agreement with the exact one for R→∞R\to\inftyR→∞ and the power expansion results for small cavities, in this way showing the robustness of our results. We have found that in general the spontaneous decay of an excited state of the atom increases with the cavity size radius and vice versa. For sufficiently small cavities the atom practically does not suffers spontaneous decay, whereas for large cavities the spontaneous decay approaches the free-space R→∞R\to\inftyR→∞ value. On the other hand, for some particular values of the cavity radius, in which the cavity is in resonance with the natural frequency of the atom, the spontaneous decay transition probability is increased compared to the free-space case. Finally, we showed how the probability spontaneous decay go from an oscillatory time behaviour, for finite cavity radius, to an almost exponential decay, for free space.
We consider a system modeled by a harmonic oscillator of frequency , coupled to the scalar potential inside a reflecting sphere of radius R. We use dressed states introduced originally in [1] and recently employed in [2] to present a non-perturbative unified description of the decay process of the system, in free space and in the case of the system being confined in a finite cavity. In the situation that we start from the initial condition that the system is in the first excited state, we give exact formulas to describe its time evolution for a cavity of arbitrary size. In the particular case of a very large cavity (free space), we recover the behaviour expected from perturbation theory in the limit of the small coupling constant. In the case of a very small cavity, our results are in good agreement with experimental observations
We consider a system consisting of an atom in the approximation of a harmonic oscillator of frequency $\overline{\ensuremath{\omega}},$ coupled to the scalar potential inside a spherical reflecting cavity of radius R. We use dressed states introduced in a previous publication [Andion, Malbouisson, and Mattos Neto, J. Phys. A 34, 3735 (2001)], which allow a nonperturbative unified description of the atom radiation process, in both cases, of a finite or an arbitrarily large cavity. We perform a study of the energy distribution in a small cavity, with the initial condition that the atom is in the first excited state and we conclude for the quasi-stability of the excited atom. For instance, for a frequency $\overline{\ensuremath{\omega}}$ of the order $\overline{\ensuremath{\omega}}\ensuremath{\sim}4.00\ifmmode\times\else\texttimes\fi{}{10}^{14}/\mathrm{s}$ (in the visible red), starting from the initial condition that the atom is in the first excited level, we find that for a cavity with diameter $2R\ensuremath{\sim}1.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6} \mathrm{m},$ the probability of the atom being at any time still in the first excited level, will be of the order of 97%. For a typical microwave frequency $\overline{\ensuremath{\omega}}\ensuremath{\sim}2.00\ifmmode\times\else\texttimes\fi{}{10}^{10}/\mathrm{s}$ we find stability in the first excited state also of the order of 97% for a cavity radius $R\ensuremath{\sim}1.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2} \mathrm{m}.$
A formalism for studying spontaneous decay of an excited two-level atom in the presence of dispersing and absorbing dielectric bodies is developed. An integral equation, which is suitable for numerical solution, is derived for the atomic upper-state-probability amplitude. The emission pattern and the power spectrum of the emitted light are expressed in terms of the Green tensor of the dielectric-matter formation, including absorption and dispersion. The theory is applied to the spontaneous decay of an excited atom at the center of a three-layered spherical cavity, with the cavity wall being modeled by a band-gap dielectric of Lorentz type. Both weak and strong coupling are studied, the latter with a special emphasis on cases where the atomic transition is (i) in the normal-dispersion zone near the medium resonance, and (ii) in the anomalous-dispersion zone associated with the band gap. In a single-resonance approximation, conditions of the appearance of Rabi oscillations and closed solutions to the evolution of the atomic state population are derived, which are in good agreement with the exact numerical results.
We consider a system consisting of a particle in the harmonic approximation, having frequency ωˉ\barωωˉ, coupled to a scalar field inside a spherical reflecting cavity of diameter LLL. By introducing {\it dressed} coordinates we define {\it dressed} states which allow a non-perturbative unified description of the radiation process, for weak and strong coupling regimes. We perform a study of the energy distribution in a small cavity, with the initial condition that the particle is in the first excited state. In the {\it weak} coupling regime, we conclude for the quasi-stability of the excited particle. For instance, for a frequency ωˉ\barωωˉ of the order ωˉ∼4.00×1014/s\barω\sim 4.00\times 10^{14}/sωˉ∼4.00×1014/s (in the visible red), starting from the initial condition that the particle is in the first excited level, we find that for a cavity with diameter L∼1.0×10−6mL\sim 1.0\times 10^{-6}mL∼1.0×10−6m, the probability that the particle be at any time still in the first excited level, will be of the order of 97%. For appropriate cavity dimensions, which are of the same order of those ensuring stability for weak coupling, we ensure for strong coupling the complete decay of the particle to the ground state in a small ellapsed time. Also we consider briefly the effects of a quartic interaction up to first order in the interaction parameter λλλ. We obtain for a large cavity an explicit λλλ-dependent expression for the particle radiation process. This formula is obtained in terms of the corresponding exact expression for the linear case and we conclude for the enhancement of the particle decay induced by the quartic interaction.
An atom, coupled linearly to an environment, is considered in a harmonic approximation in thermal equilibrium inside a cavity. The environment is modeled by an infinite set of harmonic oscillators. We employ the notion of dressed states to investigate the time evolution of the atom initially in the first excited level. In a very large cavity (free space) for a long elapsed time, the atom decays and the value of its occupation number is the physically expected one at a given temperature. For a small cavity the excited atom never completely decays and the stability rate depends on temperature.
We discuss the influence of the spontaneous decay rate of the excited state on teleportation of the atomic state via cavity decay in the scheme of Bose et al (Bose S, Knight P L, Plenio M B and Vedral V 1999 Phys. Rev. Lett. 83 5158). We show that even a small but non-zero decay rate of the excited state leads to significant effects such as lowering the probability of successful teleportation if the product of the saturation parameter and the spontaneous decay rate is not negligible in comparison with the cavity mode decay rate. We compare analytical results obtained using adiabatic elimination with the results calculated numerically.