描述自然的模式：信息与物理理论的结构

Finite de Finetti theorem for conditional probability distributions describing physical theories

We work in a general framework where the state of a physical system is defined by its behaviour under measurement and the global state is constrained by no-signalling conditions. We show that the marginals of symmetric states in such theories can be approximated by convex combinations of independent and identical conditional probability distributions, generalizing the classical finite de Finetti theorem of Diaconis and Freedman. Our results apply to correlations obtained from quantum states even when there is no bound on the local dimension, so that known quantum de Finetti theorems cannot be …

实谱非厄米理论的Hilbert空间结构

The Hilbert-Space Structure of Non-Hermitian Theories with Real Spectra

我们研究了具有非厄米哈密顿量和实谱的模型的量子力学解释。在描述了一个一般的框架来重新制定这样的模型的定义在希尔伯特空间$L_2(-\infty,\infty)$的厄米哈密顿，我们讨论的物理可观的代数的意义。

Supersymmetric theories and graphene

We discuss a 1+2 dimensional model with unconventional supersymmetry at the boundary of an AdS${}_4$, \,$\mathcal{N}$-extended supergravity. The resulting features of the supersymmetric boundary open the possibility of describing the electronic properties of graphene-like 2D materials at the Dirac points \textbf{K} and \textbf{K'}, exploiting a top-down approach. The Semenoff and Haldane-type masses entering the corresponding Dirac equations can be then extrapolated from the geometric parameters of the model describing the substrate.

Violation of no signaling in higher order quantum measure theories

More general probability sum-rules for describing interference than found in quantum mechanics (QM) were formulated by Sorkin in a hierarchy of such rules. The additivity of classical measure theory corresponds to the second sum-rule. QM violates this rule, but satisfies the third and higher sum-rules. This evokes the question of whether there are physical principles that forbid their violation. We show that under certain assumptions, violation of higher sum-rules allows for superluminal signaling.

How to make unforgeable money in generalised probabilistic theories

We discuss the possibility of creating money that is physically impossible to counterfeit. Of course, "physically impossible" is dependent on the theory that is a faithful description of nature. Currently there are several proposals for quantum money which have their security based on the validity of quantum mechanics. In this work, we examine Wiesner's money scheme in the framework of generalised probabilistic theories. This framework is broad enough to allow for essentially any potential theory of nature, provided that it admits an operational description. We prove that under a quantifiable …

时间量子理论

Temporal Quantum Theory

我们提出了一个时间量子理论的框架，用于描述与时空量子力学扩展区域相关的状态和可观测量。这一提议是以伊沙姆的历史理论为依据的。我们讨论它的关系，伊沙姆的历史理论和标准的量子力学。我们推广的Isham-Linden信息熵到本上下文中。