Quantum versus classical simultaneity in communication complexity

0509379 - MÚ 2020 RIV US eng J - Journal Article
Gavinsky, Dmitry
Quantum versus classical simultaneity in communication complexity.
IEEE Transactions on Information Theory. Roč. 65, č. 10 (2019), s. 6466-6483. ISSN 0018-9448. E-ISSN 1557-9654
R&D Projects: GA ČR(CZ) GX19-27871X
Institutional support: RVO:67985840
Keywords : communication complexity * quantum communication * quantum computing
OECD category: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8)
Impact factor: 3.036, year: 2019
Method of publishing: Limited access
http://dx.doi.org/10.1109/TIT.2019.2918453

This paper addresses two problems in the context of two-party communication complexity of functions. First, it concludes the line of research which can be viewed as demonstrating qualitative advantage of quantum communication in the three most common communication 'layouts': two-way interactive communication, one-way communication and simultaneous message passing (SMP). I demonstrate a functional problem (cEqT) over tilde, whose communication complexity is O ((log n)(2)) in the quantum version of the SMP and (Omega) over tilde(root n) in the classical (randomized) version of SMP. Second, this paper contributes to understanding the power of the weakest commonly studied regime of quantum communication-SMP with quantum messages and without shared randomness (the latter restriction can be viewed as a somewhat artificial way of making the quantum model 'as weak as possible'). Our function (cEqT) over tilde has an efficient solution in this regime as well, which means that even lacking shared randomness, quantum SMP can be exponentially stronger than its classical counterpart with shared randomness.
Permanent Link: http://hdl.handle.net/11104/0300144