17,729 research outputs found
OPE of the stress tensors and surface operators
We demonstrate that the divergent terms in the OPE of a stress tensor and a
surface operator of general shape cannot be constructed only from local
geometric data depending only on the shape of the surface. We verify this
holographically at d=3 for Wilson line operators or equivalently the twist
operator corresponding to computing the entanglement entropy using the
Ryu-Takayanagi formula. We discuss possible implications of this result.Comment: 20 pages, no figur
Study on the Rheological Properties and Constitutive Model of Shenzhen Mucky Soft Soil
In order to obtain the basic parameters of numerical analysis about the time-space effect of the deformation occurring in Shenzhen deep soft-soil foundation pit, a series of triaxial consolidated-undrained shear rheology tests on the peripheral mucky soft soil of a deep foundation pit support were performed under different confining pressures. The relations between the axial strain of the soil and time, as well as between the pore-water pressure of the soil and time, were achieved, meanwhile on the basis of analyzing the rheological properties of the soil, the relevant rheological models were built. Analysis results were proved that the rheology of Shenzhen mucky soft soil was generally viscous, elastic, and plastic, and had a low yield stress between 90 and 150 kPa. The increase in pore-water pressure made the rheological time effect of the mucky soft soil more remarkable. Thus, the drainage performance in practical engineering should be improved to its maximum possibility extent to decrease the soft-soil rheological deformation. Lastly, a six-component extended Burgers model was employed to fit the test results and the parameters of the model were determined. Findings showed that the extended Burgers model could satisfactorily simulate the various rheological stages of the mucky soft soil. The constitutive model and the determination of its parameters can be served as a foundation for the time-space effect analysis on the deformation of deep soft-soil foundation pits
Non-classical non-Gaussian state of a mechanical resonator via selectively incoherent damping in three-mode optomechanical systems
We theoretically propose a scheme for the generation of a non-classical
single-mode motional state of a mechanical resonator (MR) in the three-mode
optomechanical systems, in which two optical modes of the cavities are linearly
coupled to each other and one mechanical mode of the MR is optomechanically
coupled to the two optical modes with the same coupling strength
simultaneously. One cavity is driven by a coherent laser light. By properly
tuning the frequency of the weak driving field, we obtain engineered
Liouvillian superoperator via engineering the selective interaction Hamiltonian
confined to the Fock subspaces. In this case, the motional state of the MR can
be prepared into a non-Gaussian state, which possesses the sub-Poisson
statistics although its Wigner function is positive.Comment: 6 pages, 5 figure
Schwarzschild-de Sitter Metric and Inertial Beltrami Coordinates
Under consideration of coordinate conditions, we get the
Schwarzschild-Beltrami-de Sitter (S-BdS) metric solution of the Einstein field
equations with a cosmological constant . A brief review to the de
Sitter invariant special relativity (dS-SR), and de Sitter general relativity
(dS-GR, or GR with a ) is presented. The Beltrami metric
provides inertial reference frame for the dS-spacetime. By examining the
Schwarzschild-de Sitter (S-dS) metric existed in literatures
since 1918, we find that the existed S-dS metric describes
some mixing effects of gravity and inertial-force, instead of a pure gravity
effect arisen from "solar mass" in dS-GR. In this paper, we solve the
vacuum Einstein equation of dS-GR, with the requirement of gravity-free metric
. In this way we find S-BdS
solution of dS-GR, written in inertial Beltrami coordinates. This is a new form
of S-dS metric. Its physical meaning and possible applications are discussed.Comment: 16 pages, 1 figur
Chaos on Phase Noise of Van Der Pol Oscillator
 Phase noise is the most important parameter in many oscillators. The proposed method in this paper is based on nonlinear stochastic differential equation for phase noise analysis approach. The influences of two different sources of noise in the Van Der Pol oscillator adopted this method are compared. The source of noise is a white noise process which is a genuinely stochastic process and the other is actually a deterministic system, which exhibits chaotic behavior in some regions. The behavior of the oscillator under different conditions is investigated numerically. It is shown that the phase noise of the oscillator is affected by a noise arising from chaos than a noise arising from the genuine stochastic process at the same noise intensity
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