English
Related papers

Related papers: Lowering Helstrom Bound with non-standard coherent…

200 papers

We introduce a theory of quantum error correction (QEC) for a subclass of states within a larger Hilbert space. In the standard theory of QEC, the set of all encoded states is formed by an arbitrary linear combination of the codewords.…

Quantum Physics · Physics 2022-07-13 Maximilian Reichert , Louis W. Tessler , Marcel Bergmann , Peter van Loock , Tim Byrnes

The quantum prepare-and-measure scenario has been studied under various physical assumptions on the emitted states. Here, we first discuss how different assumptions are conceptually and formally related. We then identify one that can serve…

Quantum Physics · Physics 2025-02-19 Jef Pauwels , Stefano Pironio , Armin Tavakoli

We show that the quantum measurement known as the pretty good measurement can be used to identify an unknown quantum state picked from any set of $n$ mixed states that have pairwise fidelities upper-bounded by a constant below 1, given…

Quantum Physics · Physics 2019-11-11 Ashley Montanaro

Using Bloch's parametrization for qudits ($d$-level quantum systems), we write the Hilbert-Schmidt distance (HSD) between two generic $n$-qudit states as an Euclidean distance between two vectors of observables mean values in…

Quantum Physics · Physics 2017-10-05 Jonas Maziero

Armed with quantum correlations, quantum sensors in a network have shown the potential to outclass their classical counterparts in distributed sensing tasks such as clock synchronization and reference frame alignment. On the other hand,…

Quantum Physics · Physics 2024-05-24 Yuxiang Yang , Benjamin Yadin , Zhen-Peng Xu

We propose a general method that allows to detect the existence of normalizable ground states in supersymmetric quantum mechanical systems with non-Fredholm spectrum. We apply our method to show the existence of bound states at threshold in…

High Energy Physics - Theory · Physics 2009-10-30 M. Porrati , A. Rozenberg

Braunstein and Caves (1994) proposed to use Helstrom's {\em quantum information} number to define, meaningfully, a metric on the set of all possible states of a given quantum system. They showed that the quantum information is nothing else…

Quantum Physics · Physics 2009-10-31 O. E. Barndorff-Nielsen , R. D. Gill

Coherent states of light, and methods for distinguishing between them, are central to all applications of laser light. We obtain the ultimate quantum limit on the error probability exponent for discriminating among any M multimode…

Quantum Physics · Physics 2014-03-19 Ranjith Nair , Saikat Guha , Si-Hui Tan

This expository article gives an overview of the theory of hypothesis testing of quantum states in finite dimensional Hilbert spaces. Optimal measurement strategy for testing binary quantum hypotheses, which result in minimum error…

Quantum Physics · Physics 2018-03-14 J. Prabhu Tej , Syed Raunaq Ahmed , A. R. Usha Devi , A. K. Rajagopal

We consider the problem of discriminating two different quantum states in the setting of asymptotically many copies, and determine the optimal strategy that minimizes the total probability of error. This leads to the identification of the…

Quantum Physics · Physics 2007-05-23 K. M. R. Audenaert , J. Calsamiglia , Ll. Masanes , R. Munoz-Tapia , A. Acin , E. Bagan , F. Verstraete

In this work we determine a lower bound to the mean value of the quantum potential for an arbitrary state. Furthermore, we derive a generalized uncertainty relation that is stronger than the Robertson-Schr\"odinger inequality and hence also…

Quantum Physics · Physics 2020-05-08 F. Nicacio , F. T. Falciano

Two pure orthogonal quantum states can be perfectly distinguished by sequential local action of multiple pairs of parties. However, this process typically leads to the complete dissolution of entanglement in the states being discriminated.…

Quantum Physics · Physics 2025-06-10 Debarupa Saha , Priya Ghosh , Kornikar Sen , Chirag Srivastava , Ujjwal Sen

In the problem of asymptotic binary i.i.d. state discrimination, the optimal asymptotics of the type I and the type II error probabilities is in general an exponential decrease to zero as a function of the number of samples; the set of…

Quantum Physics · Physics 2023-01-18 Gergely Bunth , Gábor Maróti , Milán Mosonyi , Zoltán Zimborás

The uncertainty principle is a fundamental principle in quantum physics. It implies that the measurement outcomes of two incompatible observables can not be predicted simultaneously. In quantum information theory, this principle can be…

Quantum Physics · Physics 2016-06-24 F. Adabi , S. Salimi , S. Haseli

Quantum target detection is an emerging application that utilizes entanglement to enhance the sensing of the presence of an object. Although several experimental demonstrations for certain situations have been reported recently, the…

Quantum Physics · Physics 2021-07-27 Feixiang Xu , Xiao-Ming Zhang , Liang Xu , Tao Jiang , Man-Hong Yung , Lijian Zhang

A central problem in quantum information is to determine the minimal physical resources that are required for quantum computational speedup and, in particular, for fault-tolerant quantum computation. We establish a remarkable connection…

Quantum Physics · Physics 2012-11-30 Victor Veitch , Christopher Ferrie , David Gross , Joseph Emerson

We propose and investigate bounds on quantum process fidelity of quantum filters, i.e. probabilistic quantum operations represented by a single Kraus operator K. These bounds generalize the Hofmann bounds on quantum process fidelity of…

Quantum Physics · Physics 2016-08-08 Michal Sedlak , Jaromír Fiurášek

Quantum speed limits set the maximal pace of state evolution. Two well-known limits exist for a unitary time-independent Hamiltonian: the Mandelstam-Tamm and Margolus-Levitin bounds. The former restricts the rate according to the state…

Quantum Physics · Physics 2022-10-07 Gal Ness , Andrea Alberti , Yoav Sagi

We demonstrate how to discriminate two non-orthogonal, entangled quantum state which are slightly different from each other by using pseudo-Hermitian system. The positive definite metric operator which makes the pseudo-Hermitian systems…

Quantum Physics · Physics 2015-06-04 Ananya Ghatak , Bhabani Prasad Mandal

We generalize the random coding argument of stabilizer codes and derive a lower bound on the quantum capacity of an arbitrary discrete memoryless quantum channel. For the depolarizing channel, our lower bound coincides with that obtained by…

Quantum Physics · Physics 2007-05-23 Ryutaroh Matsumoto , Tomohiko Uyematsu