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In the problem of quantum state tomography, one is given $n$ copies of an unknown rank-$r$ mixed state $\rho \in \mathbb{C}^{d \times d}$ and asked to produce an estimator of $\rho$. In this work, we present the debiased Keyl's algorithm,…

Quantum Physics · Physics 2025-10-10 Angelos Pelecanos , Jack Spilecki , John Wright

It is a fundamental problem to decide how many copies of an unknown mixed quantum state are necessary and sufficient to determine the state. Previously, it was known only that estimating states to error $\epsilon$ in trace distance required…

Quantum Physics · Physics 2017-09-01 Jeongwan Haah , Aram W. Harrow , Zhengfeng Ji , Xiaodi Wu , Nengkun Yu

This paper deals with the entanglement, as quantified by the negativity, of pure quantum states chosen at random from the invariant Haar measure. We show that it is a constant (0.72037) multiple of the maximum possible entanglement. In line…

Quantum Physics · Physics 2015-05-18 Animesh Datta

We explore entanglement as a resource to distinguish locally indistinguishable orthogonal quantum states. Specifically, we consider sets which contain states from an unextendible product basis along with a pure entangled state. We establish…

Quantum Physics · Physics 2025-09-30 Abhay Srivastav , Saronath Halder

We study the problem of distinguishing quantum states using local operations and classical communication (LOCC). A question of fundamental interest is whether there exist sets of $k \leq d$ orthogonal maximally entangled states in…

Quantum Physics · Physics 2014-08-22 Alessandro Cosentino , Vincent Russo

We consider a rank regression setting, in which a dataset of $N$ samples with features in $\mathbb{R}^d$ is ranked by an oracle via $M$ pairwise comparisons. Specifically, there exists a latent total ordering of the samples; when presented…

Machine Learning · Statistics 2021-05-05 Berkan Kadioglu , Peng Tian , Jennifer Dy , Deniz Erdogmus , Stratis Ioannidis

We consider deeply the relation between the orthogonality and the distinguishability of a set of arbitrary states (including multi-partite states). It is shown that if a set of arbitrary states can be distinguished by local operations and…

Quantum Physics · Physics 2009-11-07 Ping Xing Chen , Cheng Zu Li

We compute the density of states (d.o.s.) in N coupled chains with random hopping. At zero energy, the d.o.s. shows a singularity that strongly depends on the parity of N. For odd N, the d.o.s. is proportional to 1/(E (\ln |E|)^3), with and…

Disordered Systems and Neural Networks · Physics 2009-10-31 P. W. Brouwer , C. Mudry , A. Furusaki

Estimating the trace of quantum state powers, $\text{Tr}(\rho^k)$, for $k$ identical quantum states is a fundamental task with numerous applications in quantum information processing, including nonlinear function estimation of quantum…

Quantum Physics · Physics 2025-09-03 Myeongjin Shin , Junseo Lee , Seungwoo Lee , Kabgyun Jeong

We show that no EPR-like bipartite entanglement can be distilled from a tripartite Haar random state $|\Psi\rangle_{ABC}$ by local unitaries or local operations when each subsystem $A$, $B$, or $C$ has fewer than half of the total qubits.…

Quantum Physics · Physics 2026-05-21 Zhi Li , Takato Mori , Beni Yoshida

Randomized measurements access nonlinear functionals without full tomography, yet turning third-order local single-copy data into a strong entanglement test remains difficult. We convert the reduction criterion into an experimentally…

Quantum Physics · Physics 2026-04-16 Giovanni Scala , Gniewomir Sarbicki

We analyze the restrictions on the distinguishability of quantum states imposed by special relativity. An explicit expression relating the error probability for distinguishing between two orthogonal single-photon states with the time $T$…

Quantum Physics · Physics 2009-11-07 S. N. Molotkov , S. S. Nazin

We investigate local distinguishability of quantum states by use of the convex analysis about joint numerical range of operators on a Hilbert space. We show that any two orthogonal pure states are distinguishable by local operations and…

Quantum Physics · Physics 2009-11-11 Yoshiko Ogata

We investigate three aspects of weak* convergence of the $n$-step distributions of random walks on finite volume homogeneous spaces $G/\Gamma$ of semisimple real Lie groups. First, we look into the obvious obstruction to the upgrade from…

Dynamical Systems · Mathematics 2024-05-02 Roland Prohaska

We prove a tight and close-to-optimal lower bound on the effectiveness of local quantum measurements (without classical communication) at discriminating any two bipartite quantum states. Our result implies, for example, that any two…

Quantum Physics · Physics 2022-10-26 Willian H. G. Corrêa , Ludovico Lami , Carlos Palazuelos

We show that certain families of sets in $\mathbb{R}^2$ (or $\mathbb{R}^n$) which are neither definable nor have bounded VC-dimension are nonetheless uniformly approximately definable in the real field, an o-minimal structure.

Logic · Mathematics 2026-05-12 Leonardo N. Coregliano , Maryanthe Malliaris

In this paper we illuminate the relation between entanglement and secrecy by providing the first example of a quantum state that is highly entangled, but from which, nevertheless, almost no secrecy can be extracted. More precisely, we…

Quantum Physics · Physics 2011-01-25 Matthias Christandl , Norbert Schuch , Andreas Winter

We calculate analytically the probability of large deviations from its mean of the largest (smallest) eigenvalue of random matrices belonging to the Gaussian orthogonal, unitary and symplectic ensembles. In particular, we show that the…

Statistical Mechanics · Physics 2009-11-11 David S. Dean , Satya N. Majumdar

How many copies of a mixed state $\rho \in \mathbb{C}^{d \times d}$ are needed to learn its spectrum? To date, the best known algorithms for spectrum estimation require as many copies as full state tomography, suggesting the possibility…

Quantum Physics · Physics 2025-04-04 Angelos Pelecanos , Xinyu Tan , Ewin Tang , John Wright

The classification of multipartite entanglement is essential as it serves as a resource for various quantum information processing tasks. This study concerns a particular class of highly entangled multipartite states, the so-called…

Quantum Physics · Physics 2024-11-07 N Ramadas , Arul Lakshminarayan