Atom-Field Interactions and Dressed Atoms

Compagno, G.; Passante, Roberto; Persico, F.

doi:10.1017/cbo9780511599774

Cited by 204 publications

(265 citation statements)

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“…We couple the hydrogen atom and the quantum electromagnetic field in the multipolar coupling scheme [27] …”

Section: The General Formalism For Vacuum Fluctuation and Radi-atmentioning

confidence: 99%

“…First, although the presence of the conducting boundary modifies both the vacuum fluctuations and radiation reaction (refer, for example, to Eq. (27) and Eq. (28) ), the effects of both contributions to the spontaneous excitation rate, however, cancel exactly for an atom in the ground state (ω b < ω d ) (refer to Eqs.…”

Section: Spontaneous Emission From a Uniformly Moving Atommentioning

confidence: 99%

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Spontaneous absorption of an accelerated hydrogen atom near a conducting plane in vacuum

Zhu

2006

Phys. Rev. D

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We study, in the multipolar coupling scheme, a uniformly accelerated multilevel hydrogen atom in interaction with the quantum electromagnetic field near a conducting boundary and separately calculate the contributions of the vacuum fluctuation and radiation reaction to the rate of change of the mean atomic energy. It is found that the perfect balance between the contributions of vacuum fluctuations and radiation reaction that ensures the stability of ground-state atoms is disturbed, making spontaneous transition of ground-state atoms to excited states possible in vacuum with a conducting boundary. The boundary-induced contribution is effectively a nonthermal correction, which enhances or weakens the nonthermal effect already present in the unbounded case, thus possibly making the effect easier to observe. An interesting feature worth being noted is that the nonthermal corrections may vanish for atoms on some particular trajectories. * Mailing address 1

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“…We couple the hydrogen atom and the quantum electromagnetic field in the multipolar coupling scheme [27] …”

Section: The General Formalism For Vacuum Fluctuation and Radi-atmentioning

confidence: 99%

Section: Spontaneous Emission From a Uniformly Moving Atommentioning

confidence: 99%

Spontaneous absorption of an accelerated hydrogen atom near a conducting plane in vacuum

Zhu

2006

Phys. Rev. D

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“…A two-level system (2LS) interacting with a quantum field -electromagnetic field (EMF) in particular -has proven to be a very useful model for a wide range of problems from atomic-optical [1][2][3][4][5][6][7] and condensed matter [8,9] processes to quantum computation [10]. For the latter application stringent limits in maintaining the coherence of the the 2LS (called qubits) are required .…”

Section: Introductionmentioning

confidence: 99%

Two-level atom-field interaction: Exact master equations for non-Markovian dynamics, decoherence, and relaxation

Anastopoulos

2000

Phys. Rev. A

144

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We perform a first-principles derivation of the general master equation to study the nonMarkovian dynamics of a two-level atom (2LA) interacting with an electromagnetic field (EMF). We use the influence functional method which can incorporate the full backreaction of the field on the atom, while adopting Grassmannian variables for the 2LA and the coherent state representation for the EMF. We find exact master equations for the cases of a free quantum field and a cavity field in the vacuum. In response to the search for mechanisms to preserve maximal coherence in quantum computations in ion trap prototypes, we apply these equations to analyse the decoherence of a 2LA in an EMF, and fine that decoherence time is close to relaxation time. This is at variance to the claims by authors who studied the same system but used a different coupling model. We explain the source of difference and argue that, contrary to common belief, the EMF when resonantly coupled to an atom does not decohere it as efficiently as a bath does on a quantum Brownian particle. The master-equations for non-Markovian dynamics derived here is expected to be useful for exploring new regimes of 2LA-EMF interaction, which is becoming physically important experimentally. *

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“…A two-level system (2LS) interacting with an electromagnetic field (EMF) has proven to be a very useful model for a wide range of problems from atomicoptical [2,3,4,5,6,7,8] and condensed matter [9,10] processes to quantum computation [11]. For the latter application stringent limits in maintaining the coherence of the 2LS (called qubits) are required.…”

Section: Introductionmentioning

confidence: 99%

Decoherence of two-level systems can be very different from Brownian particles

2003

Chaos, Solitons & Fractals

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In quantum computation, it is of paramount importance to locate the parameter space where maximal coherence can be preserved in the qubit system. Considerable insight in environment-induced decoherence has been gained in the last decade from detailed studies using the quantum Brownian motion (QBM) models. A number of respectable authors have applied these insights derived from QBM models to two level systems interacting with a field. Their conclusions based on this particular type of qubit coupling to the environment had led to the general belief that 2LS are easily decohered. In a recent paper [1], we debunk such a myth and caution indiscriminate application of the QBM model of decoherence to arbitrary two level systems. We point out that at least for a two-level atom (2LA)-electromagnetic field (EMF) system alone, as used in the atom cavity prototypes of quantum computers, the decoherence time is rather long, comparable to the relaxation time. In the standard Hamiltonian of the 2LA, the dominant interaction is theσ ± type of coupling between the two levels (what constitutes the qubit) and the field, not theσ z type assumed in most previous discussions of qubit decoherence, which shows the QBM behavior. Depending on the coupling the field can act as a resonator (in an atom cavity) or as a bath (in QBM) and produce very different decoherent behavior. Our conclusion is based on a new * hub@physics.umd.edu 1 exact master equation we derived at zero temperature which generalizes the text-book ones restricted by the Born-Markov approximation. Indeed many cavity experiments testify to the correctness of these results, and that the 2LA-EMF system maintaining its coherence in sufficiently long duration is the reason why experimentalists can manipulate them to show interesting quantum coherence effects.

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Atom-Field Interactions and Dressed Atoms

Cited by 204 publications

References 0 publications

Spontaneous absorption of an accelerated hydrogen atom near a conducting plane in vacuum

Spontaneous absorption of an accelerated hydrogen atom near a conducting plane in vacuum

Two-level atom-field interaction: Exact master equations for non-Markovian dynamics, decoherence, and relaxation

Decoherence of two-level systems can be very different from Brownian particles

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