arXiv subjects

Zhentao Zhang

Publications and source records attributed to Zhentao Zhang.

34 records · Page 2Linked to original sources

arXiv2025

Satellite Signal Detection via Rydberg-Atom Receiver

Rydberg-atom receivers aim for ultra-high sensitivity to microwave fields through various techniques, but receiving satellite signals has remained a significant challenge, due to the difficulty of capturing weak microwaves over long distances. In this work, we introduce a high-gain antenna to focus satellite signals, and then apply into an atomic cell via a microwave cavity. Using microwave-enhanced coupling, the minimum detectable power of incident microwave is down to -128 dBm, and the corresponding sensitivity is estimated as 21 nV/cm/Hz1/2 at frequency of 3.80 GHz. Furthermore, beacon signal from geostationary satellites is captured with Rydberg sensors for the first time, without the need for a low-noise amplifier. And C-band modulated signals are read out with a signal-to-noise ratio of 8 dB. Our results mark a significant breakthrough in facilitating satellite communications using Rydberg-atom receivers.

quant-ph↗

arXiv2025

On definable J-sets

We study definable J-sets for definable groups and compare them with weakly generic sets. We show that the property that J-sets coincide with weakly generic sets is invariant on enough saturated models, and hence a model-theoretical property. We have positive results for superstable commutative groups and some easy examples in pCF. We also give an example for noncoincidence.

math.LO↗

arXiv2025

A short note on model theory of C((t))

In this short note, we study C((t)) in the language of valued rings. We show that a definable subset of C((t))n (or in monster model, Mn) is definably compact iff it is closed and unbounded. Then we give some comments on definable groups over C((t)).

math.LO↗

arXiv2025

Presence of the negative pressure in the quantum vacuum

We investigate the microscopic origin of the negative pressure produced by the constant energy density of the vacuum. It is shown that the zero-point photons in the quantum vacuum could generate the pressures of this type in confined spaces for the photon field. We find in particular that an anomalous radiation plays a role in the occurrence of a negative pressure from the quantum vacuum.

quant-ph↗

arXiv2024

Comment on "Quantum trapping and rotational self-alignment in triangular Casimir microcavities"

Küçüköz et al., Sci. Adv. 10, eadn1825 (2024) reported an experiment, which shows that conducting plates in the misaligned system separated by a liquid may experience transverse interactions at small separations. We point out that the effects might have been examined in detail in theoretical studies, New J. Phys. 24, 113036 (2022) and Phys. Lett. A 495, 129304 (2024).

cond-mat.mes-hall↗

arXiv2024

Tangential Casimir force in the misaligned system: Magnetic media, real conductors, and a torque

Uncharged parallel plates in the misaligned system can experience a tangential Casimir force between them. We consider the role of magnetic response in this effect by extending the tangential force to magnetic media, and the extension is realized by working out the total zero-point energy of multilayered magnetodielectrics. Then we investigate the tangential force for real conductors by taking into account the temperature dependence of their dielectric constants, and obtain needed results for experimental investigations that are expected to be conducted at room temperature. Thereafter, we discuss a Casimir torque between parallel plates made of isotropic media, which offers a simple way to realize torques for uncharged surfaces.

quant-ph↗

arXiv2023

On definable $f$-generic groups and minimal flows in $p$-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 $θ$ such that $θ(r)$ is finitely satisfiable in ${\mathbb Q}_p$. Recall that the $μ$-type $μ(x)$ 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 $μ$-invariant: For any $ε\models μ$ and $a\models r$, we have $ε\cdot a\models r$. 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.

math.LO↗

arXiv2023

LMQFormer: A Laplace-Prior-Guided Mask Query Transformer for Lightweight Snow Removal

Snow removal aims to locate snow areas and recover clean images without repairing traces. Unlike the regularity and semitransparency of rain, snow with various patterns and degradations seriously occludes the background. As a result, the state-of-the-art snow removal methods usually retains a large parameter size. In this paper, we propose a lightweight but high-efficient snow removal network called Laplace Mask Query Transformer (LMQFormer). Firstly, we present a Laplace-VQVAE to generate a coarse mask as prior knowledge of snow. Instead of using the mask in dataset, we aim at reducing both the information entropy of snow and the computational cost of recovery. Secondly, we design a Mask Query Transformer (MQFormer) to remove snow with the coarse mask, where we use two parallel encoders and a hybrid decoder to learn extensive snow features under lightweight requirements. Thirdly, we develop a Duplicated Mask Query Attention (DMQA) that converts the coarse mask into a specific number of queries, which constraint the attention areas of MQFormer with reduced parameters. Experimental results in popular datasets have demonstrated the efficiency of our proposed model, which achieves the state-of-the-art snow removal quality with significantly reduced parameters and the lowest running time.

cs.CV↗

arXiv2023

On minimal flows of commutative $p$-adic groups

We study the definable topological dynamics $(G,S_G(M))$ of a definable group acting on its type space, where $M$ is a structure and $G$ is a group definable in $M$. In \cite{Newelski-I}, Newelski raised a question of whether weakly generic types coincide with almost periodic types in definable topological dynamics. In \cite{YZ-Sta}, we introduced the notion of stationarity, showing the answer is positive when $G$ is a stationary definably amenable group definable over the field of $p$-adic numbers or an $o$-minimal expansion of real closed field. In this paper, we continue with the work of \cite{YZ-Sta}, focusing on the case where $G$ is a commutative group definable over the field of $p$-adic numbers, and showing that weakly generic types coincide with almost periodic types if and only if either $G$ has definable $f$-generics or $G$ is stationary.

math.LO↗

arXiv2023

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.

math.LO↗

arXiv2022

On the Casimir effect from the zero-point energy: A tangential force and its properties

We investigate the Casimir effect in the systems that consist of parallel but misaligned finite-size plates from the point of view of zero-point energy. We elaborate the zero-point energies of the radiation field in the perfect conductor systems would generate a tangential Casimir force, and explore the properties and consequences of this tangential force in various conductor systems. Thereafter, we generalize our discussion to dielectrics. After calculating the total zero-point energies of the surface modes in the multilayered systems, we show that the tangential force also exists in dielectrics. We obtain the finite-conductivity corrections to the tangential force for imperfectly conducting plates, and calculate the finite-temperature corrections to the force. The typical strength of the tangential force suggests it might be observable.

hep-th↗

arXiv2017

Sommerfeld effect as the vertex correction in three-dimensional space

It is shown that the correction to the vertex for fermion pair annihilation and production in the low-energy region is equal to the value of the wave function for the two-body system at the origin. The procedure also shows directly that the emergence of the Sommerfeld effect in quantum mechanics is the product of the reduction of the vertex correction from four spacetime dimensions to three-dimensional space. Meanwhile, the reciprocal wave function is introduced into quantum mechanics.

hep-th↗

arXiv2016

Testing the Higgs sector directly in the nonrelativistic domain

Directly measuring the Higgs self-coupling is of great importance for testing the Brout-Englert-Higgs mechanism in the Standard Model. As a scattering that contains the direct information from the Higgs self-coupling, we investigate the process $μ^-μ^+\rightarrow HH$ in the threshold region. We calculate the one-loop corrections to the cross section and consider the non-perturbative contribution from the Higgs self-interactions in the final state. It is found that the scattering in the nonrelativistic domain could be an especial process to testing the Higgs sector directly.

hep-ph↗

arXiv2015

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.

hep-ph↗

arXiv2014

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.

quant-ph↗

arXiv2013

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.

hep-ph↗