scholarly journals Generalized Thermo Vacuum State Derived by the Partial Trace Method

2009 ◽  
Vol 26 (9) ◽  
pp. 090307 ◽  
Author(s):  
Hu Li-Yun ◽  
Fan Hong-Yi
Keyword(s):  
Vacuum State ◽  
Partial Trace ◽  
Thermo Vacuum State

Thermo vacuum state for Gaussian-enhanced chaotic light

2017 ◽  
Vol 31 (13) ◽  
pp. 1750151
Author(s):  
Wei-Feng Wu ◽  
Hong-Yi Fan
Keyword(s):  
Density Operator ◽  
Quantum Fluctuation ◽  
Photon Number ◽  
Vacuum State ◽  
Second Order ◽  
Normalization Constant ◽  
Partial Trace ◽  
Degree Of Coherence ◽  
Order Degree ◽  
Thermo Vacuum State

In nature, there exists superposition of Gaussian light and chaotic light, so we introduce the density operator for describing the Gaussian-enhanced chaotic light (GECL). By virtue of the method of integration within ordered product (IWOP) of operators, we derive its normalization constant. Then, by virtue of the partial trace method, we derive its thermo vacuum state and this may greatly simplify the calculation of photon number average and quantum fluctuation in GECL. It is demonstrated that the second-order degree of coherence of GECL is larger than 2.

FLUCTUATIONS AT FINITE TEMPERATURE AND THERMODYNAMICS OF MESOSCOPIC RLC CIRCUIT CALCULATED BY USING GENERALIZED THERMAL VACUUM STATE

2011 ◽  
Vol 25 (31) ◽  
pp. 2353-2361 ◽  
Author(s):  
HONG-CHUN YUAN ◽  
XUE-XIANG XU ◽  
XUE-FEN XU ◽  
HONG-YI FAN
Keyword(s):  
Thermal Field ◽  
Quantum Noise ◽  
Vacuum State ◽  
Nonzero Temperature ◽  
Thermal Vacuum ◽  
Partial Trace ◽  
Expectation Value ◽  
Rlc Circuit ◽  
Thermal Vacuum State ◽  
Mesoscopic Rlc Circuit

By using the partial trace method and the technique of integration within an ordered product of operators we obtain the explicit expression of the generalized thermal vacuum state (GTVS) for an RLC circuit instead of using the Takahashi–Umezawa approach. According to thermal field dynamics (TFD), namely, the expectation value of physical observables in this GTVS is equivalent to their ensemble average, based on GTVS we successfully derive the quantum fluctuations at nonzero temperature and the thermodynamical relations for the mesoscopic RLC circuit. Our results show that the higher the temperature is, the more quantum noise the RLC circuit exhibits.

Evolution of l-photon excited thermo vacuum state in a single-mode damping channel

2016 ◽  
Vol 30 (05) ◽  
pp. 1650009
Author(s):  
Rui He ◽  
Hong-Yi Fan
Keyword(s):  
Laguerre Polynomial ◽  
Hermite Polynomials ◽  
Single Mode ◽  
Vacuum State ◽  
Summation Method ◽  
Squeezing Effect ◽  
Gaussian States ◽  
State Formula ◽  
Non Gaussian ◽  
Thermo Vacuum State

In this paper, we investigate how a kind of non-Gaussian states (l-photon excited thermo vacuum state [Formula: see text]) evolves in a single-mode damping channel. We find that it evolves into a Laguerre-polynomial-weighted real–fictitious squeezed thermo vacuum state, which exhibits strong decoherence and its original nonclassicality fades. In particular, when l = 0, in this damping process the thermo squeezing effect decreases while the fictitious-mode vacuum becomes chaotic. In overcoming the difficulty of calculation, we employ the summation method within ordered product of operators, a new generating function formula about two-variable Hermite polynomials is derived.

Energy distribution in quantized mesoscopic RLC electric circuit

2016 ◽  
Vol 30 (24) ◽  
pp. 1650321
Author(s):  
Wei-Feng Wu ◽  
Hong-Yi Fan
Keyword(s):  
Energy Distribution ◽  
Quantum Information Processing ◽  
Electronic Devices ◽  
Average Energy ◽  
Electric Circuit ◽  
Vacuum State ◽  
Energy Calculation ◽  
Stable Case ◽  
Quantum Statistical ◽  
Thermo Vacuum State

Quantum information processing experimentally depends on optical-electronic devices. In this paper, we consider quantized mesoscopic RLC (resistance, inductance and capacitance) electric circuit in stable case as a quantum statistical ensemble, and calculate energy distribution (i.e. the energy stored in inductance and capacitance as well as the energy consumed on the resistance). For this aim, we employ the technique of integration within ordered product (IWOP) of operator to derive the thermo-vacuum state for this mesoscopic system, with which ensemble average energy calculation is replaced by evaluating expected value in pure state. This approach is concise and the result we deduced is physically appealling.

Thermo Vacuum State for Describing the Density Operator of Photon-subtracted Squeezed Chaotic Light

2017 ◽  
Vol 56 (10) ◽  
pp. 3188-3201
Author(s):  
Zhi-Long Wan ◽  
Hong-Yi Fan ◽  
Heng-Mei Li ◽  
Zhen Wang
Keyword(s):  
Density Operator ◽  
Vacuum State ◽  
Thermo Vacuum State

scholarly journals WIGNER FUNCTIONS OF THERMO NUMBER STATE, PHOTON SUBTRACTED AND ADDED THERMO VACUUM STATE AT FINITE TEMPERATURE

2009 ◽  
Vol 24 (28) ◽  
pp. 2263-2274 ◽  
Author(s):  
LI-YUN HU ◽  
HONG-YI FAN
Keyword(s):  
Finite Temperature ◽  
Vacuum State ◽  
Statistical Properties ◽  
Wigner Functions ◽  
New Approach ◽  
Number State ◽  
Thermo Field Dynamics ◽  
Thermo Vacuum State

Based on Takahashi–Umezawa thermo field dynamics and the order-invariance of Weyl ordered operators under similar transformations, we present a new approach to derive the exact Wigner functions of thermo number state, photon subtracted and added thermo vacuum state. We find that these Wigner functions are related to the Gaussian–Laguerre type functions of temperature, whose statistical properties are then analyzed.

scholarly journals The Dirac Electron Consistent with Proper Gravitational and Electromagnetic Field of the Kerr–Newman Solution

Galaxies ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 18
Author(s):  
Alexander Burinskii
Keyword(s):  
Electromagnetic Field ◽  
Quantum Theory ◽  
Gravitational Field ◽  
Dirac Equation ◽  
Higgs Field ◽  
Vacuum State ◽  
Relativistic String ◽  
Dirac Equations ◽  
Dirac Electron ◽  
Relativistic Scattering

The Dirac electron is considered as a particle-like solution consistent with its own Kerr–Newman (KN) gravitational field. In our previous works we considered the regularized by López KN solution as a bag-like soliton model formed from the Higgs field in a supersymmetric vacuum state. This bag takes the shape of a thin superconducting disk coupled with circular string placed along its perimeter. Using the unique features of the Kerr–Schild coordinate system, which linearizes Dirac equation in KN space, we obtain the solution of the Dirac equations consistent with the KN gravitational and electromagnetic field, and show that the corresponding solution takes the form of a massless relativistic string. Obvious parallelism with Heisenberg and Schrödinger pictures of quantum theory explains remarkable features of the electron in its interaction with gravity and in the relativistic scattering processes.

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