489 research outputs found
Multi-Sommerfeld enhancement in dark sector
We study the multi-Sommerfeld enhancement in the case where is
composed of different kinds of potentials. We show that there are special
properties of the multi-Sommerfeld enhancement. The physical content of the
multi-Sommerfeld mechanism is carefully demonstrated. The multi-Sommerfeld
enhancement might play a role in dark matter annihilation.Comment: 6 pages, 4 figure
Final state interactions at the threshold of Higgs boson pair production
We study the effect of final state interactions at the threshold of Higgs
boson pair production in the Glashow-Weinberg-Salam model. We consider three
major processes of the pair production in the model: lepton pair annihilation,
ZZ fusion, and WW fusion. We find that the corrections caused by the effect for
these processes are markedly different. According to our results, the effect
can cause non-negligible corrections to the cross sections for lepton pair
annihilation and small corrections for ZZ fusion, and this effect is negligible
for WW fusion.Comment: 5 page
Notes on the tangential Casimir force
We discuss three developments in the study of the tangential Casimir force
[Z. Zhang, New J. Phys. 24 (2022) 113036]. The first one generalizes the force
from dielectrics to magnetodielectrics. This generalization is readily realized
with the help of working out the total zero-point energy of multilayered
magnetodielectrics. The second one revisits the tangential force for real
conductors by taking into account the temperature dependence of their
dielectric constants, and provides needed theoretical results for experimental
investigations that are expected to be conducted at room temperature. The third
investigates the Casimir torque from plates made of isotropic media, which
offers a simple way to realize torques for uncharged surfaces.Comment: 9 page
On definable -generic groups and minimal flows in -adically closed fields
Let be a definable group definable over a small model . Recall that
a global type on is definable -generic over if every left
translate of is definable over . We call strongly -generic over
if every left translate of does not fork over .
Let be a group definable over the field of -adic
numbers admitting global definable -generic types over . We
show that has unboundedly many global weakly generic types iff there is a
global type on which is strongly -generic over and a
-definable function such that is finitely
satisfiable in .
Recall that the -type on is the partial type consisting of
the formulas over which define open neighborhoods of the
identity of . We show that every global weakly generic type on is
-invariant: For any and , we have
.
Let be groups definable over such that is a normal
subgroup of and is a definably compact group. Then we show that the
weakly generic types on coincide with almost periodic types iff has
boundedly many global weakly generic types
On minimal flows and definable amenability in some distal NIP theories
We study the definable topological dynamics of a definable
group acting on its type space, where is either an -minimal structure or
a -adically closed field, and a definable amenable group. We focus on
the problem raised by Neweslki of whether weakly generic types coincide with
almost periodic types, showing that the answer is positive when has
boundedly many global weakly generic types. We also give two "minimal
counterexamples" where has unboundedly many global weakly generic types,
extending the main results of "On minimal flows, definably amenable groups, and
o-minimality" to a more general context
Demonstration of Geometric Landau-Zener Interferometry in a Superconducting Qubit
Geometric quantum manipulation and Landau-Zener interferometry have been
separately explored in many quantum systems. In this Letter, we combine these
two approaches to study the dynamics of a superconducting phase qubit. We
experimentally demonstrate Landau-Zener interferometry based on the pure
geometric phases in this solid-state qubit. We observe the interference caused
by a pure geometric phase accumulated in the evolution between two consecutive
Landau-Zener transitions, while the dynamical phase is canceled out by a
spin-echo pulse. The full controllability of the qubit state as a function of
the intrinsically robust geometric phase provides a promising approach for
quantum state manipulation.Comment: 5 pages + 3 pages supplemental Materia
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