Quantum communication leads to strong correlations, that can outperform classical ones. Complementary to previous works in this area, we investigate correlations in prepare-and-measure scenarios assuming a bound on the information content of the quantum communication, rather than on its Hilbert-space dimension. Specifically, we explore the extent of classical and quantum correlations given an upper bound on the one-shot accessible information. We provide a characterisation of the set of classical correlations and show that quantum correlations are stronger than classical ones. We also show that limiting information rather than dimension leads to stronger quantum correlations. Moreover, we present device-independent tests for placing lower bounds on the information given observed correlations. Finally, we show that quantum communication carrying log⁡d bits of information is at least as strong a resource as d -dimensional classical communication assisted by pre-shared entanglement.Quantum communication leads to strong correlations, that can outperform classical ones. Complementary to previous works in this area, we investigate correlations in prepare-and-measure scenarios assuming a bound on the information content of the quantum communication, rather than on its Hilbert-space dimension. Specifically, we explore the extent of classical and quantum correlations given an upper bound on the one-shot accessible information. We provide a characterisation of the set of classical correlations and show that quantum correlations are stronger than classical ones. We also show that limiting information rather than dimension leads to stronger quantum correlations. Moreover, we present device-independent tests for placing lower bounds on the information given observed correlations. Finally, we show that quantum communication carrying log⁡d bits of information is at least as strong a resource as d -dimensional classical communication assisted by pre-shared entanglement.

arXiv:1909.05656QuantumSep 24, 202032 citations

Information theory and quantum correlations

Simon J. D. Phoenix, Stephen Mark Barnett

Lecture notes in physicsJan 1, 19910 citations

QUANTUM CORRELATIONS AND INFORMATION PROCESSING

Luis Roa-Oppliger

Jan 1, 20160 citations

Quantum communication and Bell nonlocality require infinite classical communication to simulate

Carlos de Gois, Thyago S. R. Santos, Carlos Vieira

A quantum system of any fixed dimension can be prepared in a continuum of states, yet it cannot be used to transmit an unlimited amount of classical information. Similarly, the correlations observed between measurement outcomes on separate parts of a shared quantum system can be stronger than classical correlations, but they cannot transmit information. These fundamental limitations suggest that the statistics observed from quantum communication and quantum correlations may admit a simulation using a finite amount of classical communication. This expectation is confirmed in the smallest nontrivial quantum dimension, with two classical bits being necessary and sufficient to exactly simulate qubit communication and all correlations between qubits. Despite significant efforts during the previous decades, this remained the only solved case. Here we resolve both problems for every quantum dimension. The solution reveals an unexpected qualitative transition starting at dimension four: no finite amount of classical communication can exactly simulate ququart communication nor all quantum correlations of two entangled ququarts, even with unlimited shared randomness. One might have expected this transition, if it existed, to appear already for qutrits. Instead, we construct an explicit protocol that exactly simulates qutrit communication using $357$ classical bits, and consequently, all correlations of two entangled qutrits.A quantum system of any fixed dimension can be prepared in a continuum of states, yet it cannot be used to transmit an unlimited amount of classical information. Similarly, the correlations observed between measurement outcomes on separate parts of a shared quantum system can be stronger than classical correlations, but they cannot transmit information. These fundamental limitations suggest that the statistics observed from quantum communication and quantum correlations may admit a simulation using a finite amount of classical communication. This expectation is confirmed in the smallest nontrivial quantum dimension, with two classical bits being necessary and sufficient to exactly simulate qubit communication and all correlations between qubits. Despite significant efforts during the previous decades, this remained the only solved case. Here we resolve both problems for every quantum dimension. The solution reveals an unexpected qualitative transition starting at dimension four: no finite amount of classical communication can exactly simulate ququart communication nor all quantum correlations of two entangled ququarts, even with unlimited shared randomness. One might have expected this transition, if it existed, to appear already for qutrits. Instead, we construct an explicit protocol that exactly simulates qutrit communication using $357$ classical bits, and consequently, all correlations of two entangled qutrits.

quant-pharXiv:2609.04182Sep 4, 20260 citations

Simple Quantum Communication Protocol Based on Bell Test

Yiyou Fan, Zaichen Zhang

In this paper, we propose a robust quantum communication protocol which needs Bell test only with one round classical communication. Current quantum communication protocols such as quantum dense code and quantum direct communication protocol are vulnerable to interference, and quantum key distribution protocol which have already in large scale use needs multiple rounds classical communication to remove the effects of noise. Bell test is a well-known entanglement detector and as a powerful tool to verify the quantum non-locality that the quantum correlation between two space separated objects. It has been applied in several quantum communication protocols for security check and network relay. Moreover, we found that entanglement is a valuable quantum correlation resource itself and Bell test can verify it. In our protocol, the quantum entanglement is used to establish a shared code information space between sender and receiver via the peculiar quantum correlation. The information is encoded as the position of message sequence and the receiver decodes it by a Bell Test, the maximum correlation value occurs exactly at the encoded position. The protocol completes information transmission by only one round classical communication and work well under imperfect apparatus as well. Our protocol is simple and be implemented seamlessly in existing entanglement based quantum communication protocol.In this paper, we propose a robust quantum communication protocol which needs Bell test only with one round classical communication. Current quantum communication protocols such as quantum dense code and quantum direct communication protocol are vulnerable to interference, and quantum key distribution protocol which have already in large scale use needs multiple rounds classical communication to remove the effects of noise. Bell test is a well-known entanglement detector and as a powerful tool to verify the quantum non-locality that the quantum correlation between two space separated objects. It has been applied in several quantum communication protocols for security check and network relay. Moreover, we found that entanglement is a valuable quantum correlation resource itself and Bell test can verify it. In our protocol, the quantum entanglement is used to establish a shared code information space between sender and receiver via the peculiar quantum correlation. The information is encoded as the position of message sequence and the receiver decodes it by a Bell Test, the maximum correlation value occurs exactly at the encoded position. The protocol completes information transmission by only one round classical communication and work well under imperfect apparatus as well. Our protocol is simple and be implemented seamlessly in existing entanglement based quantum communication protocol.

International Conference on Wireless Communications and Signal Processing (WCSP)Nov 1, 20221 citation

5 Quantum information and communication

Rainer Müller, Franziska Greinert

De Gruyter eBooksOct 23, 202322 citations

357

classical bits, and consequently, all correlations of two entangled qutrits.