dorsal/arxiv
View SchemaEntanglement purification of unknown quantum states
| Authors | Todd A. Brun, Carlton M. Caves, Ruediger Schack |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0010038 |
| URL | https://arxiv.org/abs/quant-ph/0010038 |
| DOI | 10.1103/PhysRevA.63.042309 |
| Journal | Phys. Rev. A 63, 042309 (2001) |
Abstract
A concern has been expressed that ``the Jaynes principle can produce fake entanglement'' [R. Horodecki et al., Phys. Rev. A {\bf 59}, 1799 (1999)]. In this paper we discuss the general problem of distilling maximally entangled states from $N$ copies of a bipartite quantum system about which only partial information is known, for instance in the form of a given expectation value. We point out that there is indeed a problem with applying the Jaynes principle of maximum entropy to more than one copy of a system, but the nature of this problem is classical and was discussed extensively by Jaynes. Under the additional assumption that the state $\rho^{(N)}$ of the $N$ copies of the quantum system is exchangeable, one can write down a simple general expression for $\rho^{(N)}$. We show how to modify two standard entanglement purification protocols, one-way hashing and recurrence, so that they can be applied to exchangeable states. We thus give an explicit algorithm for distilling entanglement from an unknown or partially known quantum state.
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"abstract": "A concern has been expressed that ``the Jaynes principle can produce fake\nentanglement\u0027\u0027 [R. Horodecki et al., Phys. Rev. A {\\bf 59}, 1799 (1999)]. In\nthis paper we discuss the general problem of distilling maximally entangled\nstates from $N$ copies of a bipartite quantum system about which only partial\ninformation is known, for instance in the form of a given expectation value. We\npoint out that there is indeed a problem with applying the Jaynes principle of\nmaximum entropy to more than one copy of a system, but the nature of this\nproblem is classical and was discussed extensively by Jaynes. Under the\nadditional assumption that the state $\\rho^{(N)}$ of the $N$ copies of the\nquantum system is exchangeable, one can write down a simple general expression\nfor $\\rho^{(N)}$. We show how to modify two standard entanglement purification\nprotocols, one-way hashing and recurrence, so that they can be applied to\nexchangeable states. We thus give an explicit algorithm for distilling\nentanglement from an unknown or partially known quantum state.",
"arxiv_id": "quant-ph/0010038",
"authors": [
"Todd A. Brun",
"Carlton M. Caves",
"Ruediger Schack"
],
"categories": [
"quant-ph"
],
"doi": "10.1103/PhysRevA.63.042309",
"journal_ref": "Phys. Rev. A 63, 042309 (2001)",
"title": "Entanglement purification of unknown quantum states",
"url": "https://arxiv.org/abs/quant-ph/0010038"
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