带SU（2）和SU（3）电荷的相干态

Classically emulated digital quantum simulation for screening and confinement in the Schwinger model with a topological term

We perform digital quantum simulation, using a classical simulator, to study screening and confinement in a gauge theory with a topological term, focusing on ($1+1$)-dimensional quantum electrodynamics (Schwinger model) with a theta term. We compute the ground state energy in the presence of probe charges to estimate the potential between them, via adiabatic state preparation. We compare our simulation results and analytical predictions for a finite volume, finding good agreements. In particular our result in the massive case shows a linear behavior for non-integer charges and a non-linear beh…

Negative string tension of higher-charge Schwinger model via digital quantum simulation

We study some properties of generalized global symmetry for the charge-$q$ Schwinger model in the Hamiltonian formalism, which is the $(1+1)$-dimensional quantum electrodynamics with a charge-$q$ Dirac fermion. This model has the $\mathbb{Z}_q$ $1$-form symmetry, which is a remnant of the electric $U(1)$ $1$-form symmetry in the pure Maxwell theory. It is known that if we put the theory on closed space, then the Hilbert space is decomposed into $q$ distinct sectors, called universes and some states with higher energy density do not decay to the ground state due to the selection rule of the $1$…

Schwinger model on an interval: analytic results and DMRG

Quantum electrodynamics in $1+1$ dimensions (Schwinger model) on an interval admits lattice discretization with a finite-dimensional Hilbert space, and is often used as a testbed for quantum and tensor network simulations. In this work we clarify the precise mapping between the boundary conditions in the continuum and lattice theories. In particular we show that the conventional Gauss law constraint commonly used in simulations induces a strong boundary effect on the charge density, reflecting the appearance of fractionalized charges. Further, we obtain by bosonization a number of exact analyt…

Schwinger 对产生中的对称性分辨纠缠

Symmetry resolved entanglement in Schwinger pair production

本文通过对称性分辨纠缠熵和电荷不平衡分辨负性，研究Schwinger效应产生的成对模式纠缠的电荷扇区结构，揭示电场如何在不同电荷扇区间转移纠缠，提供超越总度量的精细信息。

SU（N）相干态

SU(N) Coherent States

我们将SU（2）代数的Schwinger玻色子表示推广到SU（N），并利用$2(2^{N-1}-1)$玻色子谐振子的产生和湮灭算符定义了SU（N）的相干态.我们给出了SU（N）的所有（N-1）Casimirs的显式构造。属于SU（N）的任何不可约表示的SU（N）相干态用Casimir算符的本征值来标记，并用（N-1）个描述SU（N）流形的复正交向量来表征。相干态提供了一种恒等式的解决方案，满足连续性，并具有各种群论性质。

A photon model based upon chaos produced by static, Schwinger-level electric field nonlinearities that satisfies all first-order properties

In this work we postulate that Schwinger's threshold for a dynamic electric field intensity to induce spatial nonlinearity is a special case and, more generally, it is the threshold field for both static and dynamic electric fields. Fields of this magnitude induce negative energy charges to adapt positive energy attributes; within an atom they also support inter-state energy transfers and intra-state chaotic mixing of time-varying fields. Nonlinearity-induced chaos forms the basis for the probabilistic nature of photon creation. Answers to physical problems at atomic and lower scales continuou…

破缺与否：自适应量子模拟中的对称性——以Schwinger模型为例的案例研究

To break, or not to break: Symmetries in adaptive quantum simulations, a case study on the Schwinger model

该研究以格点Schwinger模型为对象，探究对称性对自适应变分量子本征求解器算符池效率的影响，发现浅电路需求下破缺平移不变性的算符池更优，而未来纠错量子器件中保留平移不变性的算符池更具前景。

Groupoids and Coherent states

Schwinger's algebra of selective measurements has a natural interpretation in terms of groupoids. This approach is pushed forward in this paper to show that the theory of coherent states has a natural setting in the framework of groupoids. Thus given a quantum mechanical system with associated Hilbert space determined by a representation of a groupoid, it is shown that any invariant subset of the group of invertible elements in the groupoid algebra determines a family of generalized coherent states provided that a completeness condition is satisfied. The standard coherent states for the harmon…