53,470 research outputs found
Takahashi Integral Equation and High-Temperature Expansion of the Heisenberg Chain
Recently a new integral equation describing the thermodynamics of the 1D
Heisenberg model was discovered by Takahashi. Using the integral equation we
have succeeded in obtaining the high temperature expansion of the specific heat
and the magnetic susceptibility up to O((J/T)^{100}). This is much higher than
those obtained so far by the standard methods such as the linked-cluster
algorithm. Our results will be useful to examine various approximation methods
to extrapolate the high temperature expansion to the low temperature region.Comment: 5 pages, 4 figures, 2 table
Chiral Primordial Gravitational Waves from a Lifshitz Point
We study primordial gravitational waves produced during inflation in quantum
gravity at a Lifshitz point proposed by Hoava. Assuming
power-counting renormalizability, foliation preserving diffeomorphism
invariance, and the condition of detailed balance, we show that primordial
gravitational waves are circularly polarized due to parity violation. The
chirality of primordial gravitational waves is a quite robust prediction of
quantum gravity at a Lifshitz point which can be tested through observations of
cosmic microwave background radiation and stochastic gravitational waves.Comment: 4 pages,2 figures;v2:reference added; v3:reference adde
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