Narrow Results

Mesoscopic damped mutual inductance coupled double resonance RLC circuit is quantized by the method of damped harmonic oscillator quantization and linear transformation. The energy levels of this circuit are given. By thermo-field dynamics (TFD), the quantum fluctuations of the current and voltage of each loop are researched in the thermal vacuum state, thermal coherent state and thermal squeezed state. It is shown that the quantum fluctuations of the current and voltage are related not only to the circuit inherent parameter and coupled magnitude of mutual inductance, but also squeezed coefficients, squeezed angle, environmental temperature and damped resistance. Furthermore, because of environmental temperature and damped resistance, the quantum fluctuations increase with the increase of temperature and decay along with time.

In this paper, we introduce the self-consistent field approximation to treat with the nonlinear interaction among spin waves. Then temperature-dependent Bogoliubov transformation is introduced to generate a new representation which engenders the transition from the zero temperature to the finite temperature. At last, temperature-dependent quantum fluctuation properties of magnons are discussed in the thermal field. At lower temperature, we find that the fluctuation of spin-component at some given time regions can be below the zero-point fluctuation level of the vacuum state and exhibit a periodical squeezing behavior. In particular, these squeezed effects vanish with the increasing of temperature. These squeezing effects differ from the previous studies.

A minimally coupled nonclassical homogeneous scalar field is examined in the flat FRW universe in the semiclassical theory of gravity. Particle production in thermal coherent and squeezed states is studied for the flat FRW universe, in the oscillatory phase of the inflaton. Solutions for the semiclassical Friedmann equations are obtained in the thermal nonclassical states. Validity of the semiclassical theory is examined in the thermal coherent and squeezed states in the oscillatory phase of inflaton. Particle creation can be enhanced due to thermal and quantum effects. Quantum fluctuations of the inflaton in thermal coherent and squeezed state formalisms are also studied. Classical gravity differ from semiclassical gravity in the thermal coherent state only by an amplitude factor.

The generated gravitational waves during inflation are placed in thermal squeezed vacuum state. The B mode angular power spectrum of the CMB anisotropy is found enhanced for all multipole moments l ⩾ 2 but less than the upper bound of the WMAP 7-year data.