Multi-Sommerfeld enhancement in dark sector

We study the multi-Sommerfeld enhancement in the case where $V(r)$ 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 ff-generic groups and minimal flows in pp-adically closed fields

Let $X$ be a definable group definable over a small model $M_0$. Recall that a global type $p$ on $X$ is definable $f$-generic over $M_0$ if every left translate of $p$ is definable over $M_0$. We call $p$ strongly $f$-generic over $M_0$ if every left translate of $p$ does not fork over $M_0$. Let $H$ be a group definable over the field ${\mathbb Q}_p$ of $p$-adic numbers admitting global definable $f$-generic types over ${\mathbb Q}_p$. We show that $H$ has unboundedly many global weakly generic types iff there is a global type $r$ on $H$ which is strongly $f$-generic over ${\mathbb Q}_p$ and a ${\mathbb Q}_p$-definable function $\theta$ such that $\theta(r)$ is finitely satisfiable in ${\mathbb Q}_p$. Recall that the $\mu$-type $\mu(x)$ on $H$ is the partial type consisting of the formulas over ${\mathbb Q}_p$ which define open neighborhoods of the identity of $H$. We show that every global weakly generic type $r$ on $H$ is $\mu$-invariant: For any $\epsilon\models \mu$ and $a\models r$, we have $\epsilon\cdot a\models r$. Let $G$ be groups definable over ${\mathbb Q}_p$ such that $H$ is a normal subgroup of $G$ and $G/H$ is a definably compact group. Then we show that the weakly generic types on $G$ coincide with almost periodic types $G$ iff $G$ has boundedly many global weakly generic types

On minimal flows and definable amenability in some distal NIP theories

We study the definable topological dynamics $(G(M), S_G(M))$ of a definable group acting on its type space, where $M$ is either an $o$-minimal structure or a $p$-adically closed field, and $G$ 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 $G$ has boundedly many global weakly generic types. We also give two "minimal counterexamples" where $G$ 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