Bibliographic Details
| Title: |
Classical Communications with Indefinite Causal Order for $N$ completely depolarizing channels |
| Authors: |
Sazim, Sk, Sedlak, Michal, Singh, Kratveer, Pati, Arun Kumar |
| Source: |
Phys. Rev. A 103, 062610 (2021) |
| Publication Year: |
2020 |
| Collection: |
Quantum Physics |
| Subject Terms: |
Quantum Physics |
| More Details: |
If two identical copies of a completely depolarizing channel are put into a superposition of their possible causal orders, they can transmit non-zero classical information. Here, we study how well we can transmit classical information with $N$ depolarizing channels put in superposition of $M$ causal orders via quantum SWITCH. We calculate Holevo quantity if the superposition uses only cyclic permutations of channels and find that it increases with $M$ and it is independent of $N$. For a qubit it never reaches $1$ if we are increasing $M$. On the other hand, the classical capacity decreases with the dimension $d$ of the message system. Further, for $N=3$ and $N=4$ we studied superposition of all causal orders and uniformly superposed causal orders belonging to different cosets created by cyclic permutation subgroup.
Comment: 16pages, 8figures, and 2tables. Thoroughly revised with a major revision in Section.IV. A new Author has been added. Comments are welcome |
| Document Type: |
Working Paper |
| DOI: |
10.1103/PhysRevA.103.062610 |
| Access URL: |
http://arxiv.org/abs/2004.14339 |
| Accession Number: |
edsarx.2004.14339 |
| Database: |
arXiv |
