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Search Results: 1 - 10 of 67252 matches for " Zhong Chao Wu "
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A Proposal of Testing Imaginary Time in a Total Reflection
Zhong Chao Wu
Physics , 2008,
Abstract: All paradoxes concerning faster-than-light signal propagation reported in recent experiments can be dispelled by using imaginary time in a quantum framework. I present a proposal of testing imaginary time in a total reflection.
The Imaginary Time in the Tunneling Process
Zhong Chao Wu
Physics , 2008,
Abstract: By using techniques developed in quantum cosmology, it is found that a tunneling particle spends purely imaginary time on a barrier region. The {\it imaginary} time is associated with the stochastic acausal behaviour of a state, while the {\it real} time is associated with the deterministic causal evolution of a state. For the tunneling case the nonzero imaginary time is associated with the transmission rate of the tunneling process, which is related to the thickness of the barrier. The physical meaning of the zero real time is that the particle instantly jumps from one side of the barrier to the other regardless of the thickness. This leads to the illusion that tunneling particles could actually travel faster than light. The results of recent experiments in quantum optics concerning tunneling time can be thought of as the first experimental confirmation of the existence of imaginary time. Relativity is not violated.
Inverse Temperature 4-vector in Special Relativity
Zhong Chao Wu
Physics , 2008, DOI: 10.1209/0295-5075/88/20005
Abstract: There exist several prescriptions for identifying the notion of temperature in special relativity. We argue that the inverse temperature 4-vector $\bf \beta$ is the only viable option from the laws of thermodynamics, and $\bf \beta$ is a future-directed timelike 4-vector. Using a superfluidity thought experiment, one can show that $\bf \beta$ is not necessarily along the time direction of the comoving frame of the system, as is usually thought. It is conjectured that, for an isolated system, the 4-vector is determined from the entropy-maximum principle.
Causality, Time Arrow and Half Cycling Universe
Wu Zhong Chao
Physics , 1998,
Abstract: If one introduces causality into quantum cosmology, then the prescription for the no-boundary universe should be revised. We show that the thermodymanic arrow of time associated with the perturbation modes should be reversed at the maximum expansion for the oscillating Hawking model. To an observer equipped with the time arrow, the universe will terminate its evolution after an half cycle.
No-boundary Codimension-two Braneworld
Zhong Chao Wu
Physics , 2004,
Abstract: The quantum creation probability and entropy of a 2-codimensional braneworld are calculated in the framework of no-boundary universe. The entropy can take an arbitrarily large value as the brane tensions increase, in violation of the conjectured "N-bound" in quantum gravity, even for a 4-dimensional ordinary universe.
Pair Creation of Black Hole in Anti-de Sitter Space Background
Wu Zhong Chao
Physics , 1998, DOI: 10.1016/S0370-2693(98)01509-3
Abstract: In the absence of a general no-boundary proposal for open creation, the complex constrained instanton is used as the seed for the open pair creations of black holes in the Kerr-Newman-anti-de Sitter family. The relative probability of the chargeless and nonrotating black hole pair is the exponential of the negative of the entropy, and that of the charged and (or) rotating black hole pair is the exponential of the negative of one quarter of the sum of the outer and inner black hole horizon areas.
Pair Creation of Black Holes in Anti-de Sitter Space Background (I)
Wu Zhong Chao
Physics , 1998, DOI: 10.1023/A:1018896211493
Abstract: For a spherically symmetric vacuum model with a negative cosmological constant, a complex constrained instanton is considered as the seed for the quantum pair creation of Schwarzschild-anti-de Sitter black holes. The relative creation probability is found to be the exponential of the negative of the black hole entropy. The black hole entropy is known to be one quarter of the black hole horizon area. In the absence of a general no-boundary proposal for open creation, the constrained instanton approach is used in treating both the open and closed pair creations of black holes.
Open and Closed Creations of Black Holes
Wu Zhong Chao
Physics , 1998,
Abstract: We study pair creation of Kerr-Newman-anti-de Sitter and Kerr-Newman-de Sitter black holes.
Commutativity of Substitution and Variation in Actions of Quantum Field Theory
Zhong Chao Wu
Physics , 2008, DOI: 10.1103/PhysRevD.80.105001
Abstract: There exists a paradox in quantum field theory: substituting a field configuration which solves a subset of the field equations into the action and varying it is not necessarily equivalent to substituting that configuration into the remaining field equations. We take the $S^4$ and Freund-Rubin-like instantons as two examples to clarify the paradox. One must match the specialized configuration field variables with the corresponding boundary conditions by adding appropriate Legendre terms to the action. Some comments are made regarding exceptional degenerate cases.
Quantum Black Hole
Wu Zhong Chao
Physics , 1998,
Abstract: Creation of a black hole in quantum cosmology is the third way of black hole formation. In contrast to the gravitational collapse from a massive body in astrophysics or from the quantum fluctuation of matter fields in the very early universe, in quantum cosmology scenario the black hole is essentially created from nothing. The black hole originates from a constrained gravitational instanton. The probability of creation for all kinds of single black holes in the Kerr- Newman-de Sitter family, at the semi-classical level, is the exponential of the total entropy of the universe, or one quarter of the sum of both the black hole and the cosmological horizon areas. The de Sitter spacetime is the most probable evolution at the Planckian era.
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