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Almost qudits in the prepare-and-measure scenario
- Source :
- Phys. Rev. Lett. 129, 250504 (2022)
- Publication Year :
- 2022
-
Abstract
- Quantum communication is often investigated in scenarios where only the dimension of Hilbert space is known. However, assigning a precise dimension is often an approximation of what is actually a higher-dimensional process. Here, we introduce and investigate quantum information encoded in carriers that nearly, but not entirely, correspond to standard qudits. We demonstrate the relevance of this concept for semi-device-independent quantum information by showing how small higher-dimensional components can significantly compromise the conclusions of established protocols. Then we provide a general method, based on semidefinite relaxations, for bounding the set of almost qudit correlations, and apply it to remedy the demonstrated issues. This method also offers a novel systematic approach to the well-known task of device-independent tests of classical and quantum dimensions with unentangled devices. Finally, we also consider viewing almost qubit systems as a physical resource available to the experimenter and determine the optimal quantum protocol for the well-known Random Access Code.<br />Comment: 5 + 5 pages, 6 figures. Changelog: v2 minor correction
- Subjects :
- Quantum Physics
Subjects
Details
- Database :
- arXiv
- Journal :
- Phys. Rev. Lett. 129, 250504 (2022)
- Publication Type :
- Report
- Accession number :
- edsarx.2208.07887
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1103/PhysRevLett.129.250504