548 research outputs found
Hodge structures associated to SU(p,1)
Let A be an abelian variety over C such that the semisimple part of the Hodge
group of A is a product of copies of SU(p,1) for some p>1. We show that any
effective Tate twist of a Hodge structure occurring in the cohomology of A is
isomorphic to a Hodge structure in the cohomology of some abelian variety
Coherent inelastic backscattering of intense laser light by cold atoms
We present a nonperturbative treatment of coherent backscattering of intense
laser light from cold atoms, and predict a nonvanishing backscattering signal
even at very large intensities, due to the constructive (self-)interference of
inelastically scattered photons.Comment: minor change
Thermoelectric response near a quantum critical point of beta-YbAlB4 and YbRh2Si2: A comparative study
The thermoelectric coefficients have been measured on the Yb-based heavy
fermion compounds beta-YbAlB4 and YbRh2Si2 down to a very low temperature. We
observe a striking difference in the behavior of the Seebeck coefficient, S in
the vicinity of the Quantum Critical Point (QCP) in the two systems. As the
critical field is approached, S/T enhances in beta-YbAlB4 but is drastically
reduced in YbRh2Si2. While in the former system, the ratio of
thermopower-to-specific heat remains constant, it drastically drops near the
QCP in YbRh2Si2. In both systems, on the other hand, the Nernst coefficient
shows a diverging behavior near the QCP. The results provide a new window to
the way various energy scales of the system behave and eventually vanish near a
QCP
Deterministic Weak Localization in Periodic Structures
The weak localization is found for perfect periodic structures exhibiting
deterministic classical diffusion. In particular, the velocity autocorrelation
function develops a universal quantum power law decay at 4 times Ehrenfest
time, following the classical stretched-exponential type decay. Such
deterministic weak localization is robust against weak enough randomness (e.g.,
quantum impurities). In the 1D and 2D cases, we argue that at the quantum limit
states localized in the Bravis cell are turned into Bloch states by quantum
tunnelling.Comment: 5 pages, 2 figure
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