6,378 research outputs found
Holographic Butterfly Effect at Quantum Critical Points
When the Lyapunov exponent in a quantum chaotic system saturates
the bound , it is proposed that this system has a
holographic dual described by a gravity theory. In particular, the butterfly
effect as a prominent phenomenon of chaos can ubiquitously exist in a black
hole system characterized by a shockwave solution near the horizon. In this
paper we propose that the butterfly velocity can be used to diagnose quantum
phase transition (QPT) in holographic theories. We provide evidences for this
proposal with an anisotropic holographic model exhibiting metal-insulator
transitions (MIT), in which the derivatives of the butterfly velocity with
respect to system parameters characterizes quantum critical points (QCP) with
local extremes in zero temperature limit. We also point out that this proposal
can be tested by experiments in the light of recent progress on the measurement
of out-of-time-order correlation function (OTOC).Comment: 7 figures, 15 page
Customers\u27 Acceptance of a Web Site for Product Information Search
A theoretical model of consumers’ acceptance of a website to search for product information is constructed and empirically assessed in this study. The results suggest that, besides perceived usefulness and perceived ease of use, the concepts of perceived costs and perceived risks should be incorporated into the technology acceptance model to account for information search behavior on the new media. Moreover, the causal relationship between use intention and its antecedents is significantly different for search goods and experience goods. To support the task of product information search on a website, product categorization and consumers’ evaluation of product quality information should be taken into consideration for website design. That is, the WWW technological applications employed to support product information search for search goods should be different from those used for experience goods
Holographic Metal-Insulator Transition in Higher Derivative Gravity
We introduce a Weyl term into the Einstein-Maxwell-Axion theory in four
dimensional spacetime. Up to the first order of the Weyl coupling parameter
, we construct charged black brane solutions without translational
invariance in a perturbative manner. Among all the holographic frameworks
involving higher derivative gravity, we are the first to obtain metal-insulator
transitions (MIT) when varying the system parameters at zero temperature.
Furthermore, we study the holographic entanglement entropy (HEE) of strip
geometry in this model and find that the second order derivative of HEE with
respect to the axion parameter exhibits maximization behavior near quantum
critical points (QCPs) of MIT. It testifies the conjecture in 1502.03661 and
1604.04857 that HEE itself or its derivatives can be used to diagnose quantum
phase transition (QPT).Comment: 20 pages, 4 figures; typo corrected, added 3 references; minor
revisio
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