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We investigate quantum state discrimination with confidentiality. $N$ observers share a given quantum state belonging to a finite set of known states. The observers want to determine the state as accurately as possible and send a…

Quantum Physics · Physics 2015-06-30 Kenji Nakahira , Tsuyoshi Sasaki Usuda , Kentaro Kato

The use of parity-check gates in information theory has proved to be very efficient. In particular, error correcting codes based on parity checks over low-density graphs show excellent performances. Another basic issue of information…

Disordered Systems and Neural Networks · Physics 2007-05-23 S. Ciliberti , M. Mezard , R. Zecchina

Consider binary linear codes obtained from bipartite graphs as follows. There are~\(k \geq 1\) left nodes each representing a message bit and there are~\(m = m(k)\) right nodes each representing a parity bit, generated from the…

Probability · Mathematics 2017-09-13 Ghurumuruhan Ganesan

We analytically derive the bit-string probability distributions of subsystems of random pure states and depolarized random states using the Dirichlet distribution. We identify the exact Beta distribution as the universal statistical law of…

Quantum Physics · Physics 2026-02-24 Sangchul Oh

We investigate how a classical private key can be used by two players, connected by an insecure one-way quantum channel, to perform private communication of quantum information. In particular we show that in order to transmit n qubits…

Quantum Physics · Physics 2007-05-23 Michele Mosca , Alain Tapp , Ronald de Wolf

Quantum Bit String Comparators (QBSC) operate on two sequences of n-qubits, enabling the determination of their relationships, such as equality, greater than, or less than. This is analogous to the way conditional statements are used in…

Quantum Physics · Physics 2023-11-23 Khuram Shahzad , Omar Usman Khan

We study the query complexity of Weak Parity: the problem of computing the parity of an n-bit input string, where one only has to succeed on a 1/2+eps fraction of input strings, but must do so with high probability on those inputs where one…

Computational Complexity · Computer Science 2013-12-03 Scott Aaronson , Andris Ambainis , Kaspars Balodis , Mohammad Bavarian

The one-bit quanta image sensor is a photon-counting device that produces binary measurements where each bit represents the presence or absence of a photon. In the presence of read noise, the sensor quantizes the analog voltage into the…

Signal Processing · Electrical Eng. & Systems 2023-02-01 Stanley H. Chan

Quantum information is defined by applying the concepts of ordinary (Shannon) information theory to a quantum sample space consisting of a single framework or consistent family. A classical analogy for a spin-half particle and other…

Quantum Physics · Physics 2009-11-07 Robert B. Griffiths

On a quantum particle in the unit interval $[0,1]$, perform a position measurement with inaccuracy $1/n$ and then a quantum measurement of the projection $|\phi\rangle\langle\phi|$ with some arbitrary but fixed normalized $\phi$. Call the…

Quantum Physics · Physics 2026-02-26 Xabier Oianguren-Asua , Roderich Tumulka

A quantum system (quanton) traverses an interferometer with $N$ equally probable paths and interacts with another quantum system (detector) that stores path information in a set of symmetric states. In this interferometric framework, we…

Quantum Physics · Physics 2026-01-21 L. F. Melo , O. Jiménez , L. Neves

We consider a special form of state discrimination in which after the measurement we are given additional information that may help us identify the state. This task plays a central role in the analysis of quantum cryptographic protocols in…

Quantum Physics · Physics 2011-05-02 Deepthi Gopal , Stephanie Wehner

A quantum encryption scheme (also called private quantum channel, or state randomization protocol) is a one-time pad for quantum messages. If two parties share a classical random string, one of them can transmit a quantum state to the other…

Quantum Physics · Physics 2007-05-23 Andris Ambainis , Adam Smith

Kolmogorov complexity is a measure of the information contained in a binary string. We investigate here the notion of quantum Kolmogorov complexity, a measure of the information required to describe a quantum state. We show that for any…

Quantum Physics · Physics 2007-05-23 C. Mora , H. Briegel , B. Kraus

We present a formula that determines the optimal number of qubits per message that allows asymptotically faithful compression of the quantum information carried by an ensemble of mixed states. The set of mixed states determines a…

Quantum Physics · Physics 2009-11-07 Masato Koashi , Nobuyuki Imoto

Measurements play an important role in quantum computing (QC), by either providing the nonlinearity required for two-qubit gates (linear optics QC), or by implementing a quantum algorithm using single-qubit measurements on a highly…

Quantum Physics · Physics 2008-11-17 Radu Ionicioiu , Anca E. Popescu , William J. Munro , Timothy P. Spiller

In this paper, we study quantum dense coding between two arbitrarily fixed particles in a (N+2)-particle maximally-entangled states through introducing an auxiliary qubit and carrying out local measurements. It is shown that the transmitted…

Quantum Physics · Physics 2009-11-10 Jian-Lan Chen , Le-Man Kuang

We establish quantum uncloneable encryption with unconditional security, preventing two non-communicating adversaries from simultaneously decrypting a single ciphertext $-$ even when both are given the key. Our construction achieves…

Quantum Physics · Physics 2026-03-11 Archishna Bhattacharyya , Anne Broadbent , Eric Culf

Quantum entanglement cannot be unlimitedly shared among arbitrary number of qubits. Larger the number of entangled pairs in an N-qubit system, smaller the degree of bi-partite entanglement is. We analyze a system of N qubits in which an…

Quantum Physics · Physics 2009-11-06 Masato Koashi , Vladimir Buzek , Nobuyuki Imoto

Parity check matrices (PCMs) are used to define linear error correcting codes and ensure reliable information transmission over noisy channels. The set of codewords of such a code is the null space of this binary matrix. We consider the…

Information Theory · Computer Science 2020-05-12 Luís M. S. Russo , Tobias Dietz , José Rui Figueira , Alexandre P. Francisco , Stefan Ruzika