Thermal squeezed states in thermo field dynamics and quantum and thermal fluctuations

Kireev, A. N.; Mann, A.; Revzen, M.; Umezawa, H.

doi:10.1016/0375-9601(89)90317-4

Cited by 29 publications

(10 citation statements)

References 12 publications

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“…2. By the way, as is well known [25], there appear thermal squeezed states on the dissipative TFD theory. However, the present study does not consider the phase properties because it is not essential for the present discussions.…”

Section: Summary and Discussionmentioning

confidence: 83%

A new perspective to formulate a dissipative thermo field dynamics

Hashizume

Suzuki

Okamura

2015

Physica A: Statistical Mechanics and its Applications

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In the present study, we propose a new perspective on thermal dissipation based on the thermo field dynamics. From the view point of the renormalization theory, there appear effective interactions between the original and tilde spaces on thermo field dynamics with reducing thermal disturbances. This study yields the equivalence of the following two pictures, namely such a spin system with a random field due to a heat bath as is defined in a Hilbert space and a finite-size system with effective interactions defined in a double Hilbert space. The correspondence of the above two systems yields such perspective that the thermal disturbance is described by the effective non-Hermitian interactions.Comment: 12pages 2figure

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Section: Summary and Discussionmentioning

confidence: 83%

A new perspective to formulate a dissipative thermo field dynamics

Hashizume

Suzuki

Okamura

2015

Physica A: Statistical Mechanics and its Applications

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“…From now on, we call this state the thermal coherent state [30,31,32]. Moreover, for simplicity, we assume α characterizing |α; θ B to be always real.…”

Section: A Brief Review Of the Tfdmentioning

confidence: 99%

Thermal Effects in Jaynes–cummings Model Derived With Low-Temperature Expansion

Azuma

Ban

2011

Int. J. Mod. Phys. C

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In this paper, we investigate thermal effects of the Jaynes-Cummings model (JCM) at finite temperature with a perturbative approach. We assume a single two-level atom and a single cavity mode to be initially in the thermal equilibrium state and the thermal coherent state, respectively, at a certain finite low temperature. Describing this system with Thermo Field Dynamics formalism, we obtain a low-temperature expansion of the atomic population inversion in a systematic manner. Letting the system evolve in time with the JCM Hamiltonian, we examine thermal effects of the collapse and the revival of the Rabi oscillations by means of the third-order perturbation theory under the low-temperature limit, that is to say, using the low-temperature expansion up to the third order terms. From an intuitive discussion, we can expect that the period of the revival of the Rabi oscillations becomes longer as the temperature rises. Numerical results obtained with the perturbation theory reproduce well this temperature dependence of the period.

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“…Moreover, different from the properties of the position and momentum, the average value and variance of the particle number operator as well as the second-order correlation function are time-independent.Introducing finite temperature effects into squeezed states is important, because a squeezed state can possesses minimum uncertainty and squeezability and accordingly technological applicability [1] and, on the other hand, a finite-temperature influence on it is inevitable. This problem has received extensive investigations [2][3][4][5][6][7][8][9][10][11]. Analyzing these investigations, Ref.…”

mentioning

confidence: 99%

“…Introducing finite temperature effects into squeezed states is important, because a squeezed state can possesses minimum uncertainty and squeezability and accordingly technological applicability [1] and, on the other hand, a finite-temperature influence on it is inevitable. This problem has received extensive investigations [2][3][4][5][6][7][8][9][10][11]. Analyzing these investigations, Ref.…”

mentioning

confidence: 99%

“…Analyzing these investigations, Ref. [2,3] divided the squeezed states with finite temperature effects into the thermalized squeezed states [4][5][6] and the squeezed thermal states [7][8][9][10][11]. The thermalized squeezed states and the squeezed thermal states are physically distinct states, albeit they are turned into each other by some parameter transformation [3].…”

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confidence: 99%

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Thermalized displaced squeezed thermal states

Lü

2000

J. Phys. A: Math. Gen.

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In the coordinate representation of thermofield dynamics, we investigate the thermalized displaced squeezed thermal state which involves two temperatures successively. We give the wavefunction and the matrix element of the density operator at any time, and accordingly calculate some quantities related to the position, momentum and particle number operator, special cases of which are consistent with the results in the literature. The two temperatures have different correlations with the squeeze and coherence components. Moreover, different from the properties of the position and momentum, the average value and variance of the particle number operator as well as the second-order correlation function are time-independent.Introducing finite temperature effects into squeezed states is important, because a squeezed state can possesses minimum uncertainty and squeezability and accordingly technological applicability [1] and, on the other hand, a finite-temperature influence on it is inevitable. This problem has received extensive investigations [2][3][4][5][6][7][8][9][10][11]. Analyzing these investigations, Ref. [2,3] divided the squeezed states with finite temperature effects into the thermalized squeezed states [4][5][6] and the squeezed thermal states [7][8][9][10][11]. The thermalized squeezed states and the squeezed thermal states are physically distinct states, albeit they are turned into each other by some parameter transformation [3]. Each of these two states has its several possible representations, and Ref.[2] gave a detailed discussion about them and elucidated their physical interpretations. From Ref.[2], it is not difficult to understand that the squeezed thermal states correspond to the output from a squeezed device whose input is a thermal chaotic state with Bose-Einstein distribution, while the thermalized squeezed states are prepared by thermalizing a squeezed state provided the thermalizing source is such a device that it can bring a vacuum state into a thermal chaotic state. Both the thermalized squeezed state and the squeezed thermal state are involved in one thermal source only. In this paper, we intend to consider yet another different state which we call the thermalized displaced squeezed thermal state (TDSTS). This state can be prepared by thermalizing a displaced squeezed thermal state, and obviously contains the thermalized displaced squeezed state (TDSS) and the displaced squeezed thermal state (DSTS) as its special cases. The TDSTS is involved in two thermal sources successively and perhaps is more practical than the TDSS and the DSTS, because, in general, there exist thermal noises for the input and output of a displacement-squeeze device which generates a displaced squeezed state, and furthermore the thermal noises have perhaps different temperatures for the input and output, respectively.In this paper, within the framework of thermofield dynamics [12,13], we shall first give the definition of the thermalized displaced squeezed state, then give the time-dependent wavefunction and calcula...

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Thermal squeezed states in thermo field dynamics and quantum and thermal fluctuations

Cited by 29 publications

References 12 publications

A new perspective to formulate a dissipative thermo field dynamics

A new perspective to formulate a dissipative thermo field dynamics

Thermal Effects in Jaynes–cummings Model Derived With Low-Temperature Expansion

Thermalized displaced squeezed thermal states

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