34,451 research outputs found
Non-perturbative approach for the time-dependent symmetry breaking
We present a variational method which uses a quartic exponential function as
a trial wave-function to describe time-dependent quantum mechanical systems. We
introduce a new physical variable which is appropriate to describe the
shape of wave-packet, and calculate the effective action as a function of both
the dispersion and . The effective potential
successfully describes the transition of the system from the false vacuum to
the true vacuum. The present method well describes the long time evolution of
the wave-function of the system after the symmetry breaking, which is shown in
comparison with the direct numerical computations of wave-function.Comment: 8 pages, 3 figure
Quantum field and uniformly accelerated oscillator
We present an exact treatment of the influences on a quantum scalar field in
its Minkowski vacuum state induced by coupling of the field to a uniformly
accelerated harmonic oscillator. We show that there are no radiation from the
oscillator in the point of view of a uniformly accelerating observer. On the
other hand, there are radiations in the point of view of an inertial observer.
It is shown that Einstein-Podolsky-Rosen (EPR) like correlations of Rindler
particles in Minkowski vacuum states are modified by a phase factor in front of
the momentum-symmetric Rindler operators. The exact quantization of a
time-dependent oscillator coupled to a massless scalar field was given.Comment: 28 pages, LaTe
Supersolid Helium at High Pressure
We have measured the pressure dependence of the supersolid fraction by a
torsional oscillator technique. Superflow is found from 25.6 bar up to 136.9
bar. The supersolid fraction in the low temperature limit increases from 0.6 %
at 25.6 bar near the melting boundary up to a maximum of 1.5% near 55 bar
before showing a monotonic decrease with pressure extrapolating to zero near
170 bar.Comment: 4 pages, 4 figure
Quantum entanglement of bound particles under free center of mass dispersion
On the basis of the full analytical solution of the overall unitary dynamics,
the time evolution of entanglement is studied in a simple bipartite model
system evolving unitarily from a pure initial state. The system consists of two
particles in one spacial dimension bound by harmonic forces and having its free
center of mass initially localized in space in a minimum uncertainty wave
packet. The existence of such initial states in which the bound particles are
not entangled is pointed out. The entanglement of the two particles is shown to
be independent of the wavepacket mean momentum, and to increase monotonically
in a time scale distinct from that of the spreading of the center of mass
wavepacket.Comment: 17 pages, 5 figure
The role of cool versus warm colors in B2B versus B2C firm-generated content for boosting positive eWOM
While the importance of electronic Word-of-Mouth (eWOM) for Business-to-Business (B2B) firms is increasing, the use of B2B firm-generated content for driving positive eWOM is less understood. Given the emergence of image-oriented social media platforms, this study investigates how color features increase positive eWOM in the B2B versus B2C context by analyzing 13,356 images on Instagram. The results reveal key differences in color features in the contexts of B2B and B2C. Specifically, cool colors are more appealing in B2B content, while warm colors work better in B2C content. Further, darkness, saturation, and colorfulness moderate the cool effect in B2B content, such that darker, less saturated, and more varied colors increase the effect of cool color. In the B2C context, only colorfulness increases the effect of warm color. The findings of this research contribute to the literature examining the different drivers of eWOM between B2B and B2C social media and offer managerial implications for B2B and B2C firms on ways to encourage positive eWOM
Scalar Wave Falloff in Asymptotically Anti-de Sitter Backgrounds
Conformally invariant scalar waves in black hole spacetimes which are
asymptotically anti-de Sitter are investigated. We consider both the
-dimensional black hole and -dimensional Schwarzschild-anti-de
Sitter spacetime as backgrounds. Analytical and numerical methods show that the
waves decay exponentially in the dimensional black hole background.
However the falloff pattern of the conformal scalar waves in the
Schwarzschild-anti-de Sitter background is generally neither exponential nor an
inverse power rate, although the approximate falloff of the maximal peak is
weakly exponential. We discuss the implications of these results for mass
inflation.Comment: 34 pages, Latex, 26 figures, uses psfi
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