dorsal/arxiv
View SchemaHow to hide a secret direction
| Authors | E. Bagan, J. Calsamiglia, R. Demkowicz-Dobrzanski, R. Munoz-Tapia |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0606165 |
| URL | https://arxiv.org/abs/quant-ph/0606165 |
| DOI | 10.1088/1367-2630/9/8/244 |
| Journal | New J. Phys. 9 (2007) 244 |
Abstract
We present a procedure to share a secret spatial direction in the absence of a common reference frame using a multipartite quantum state. The procedure guarantees that the parties can determine the direction if they perform joint measurements on the state, but fail to do so if they restrict themselves to local operations and classical communication (LOCC). We calculate the fidelity for joint measurements, give bounds on the fidelity achievable by LOCC, and prove that there is a non-vanishing gap between the two of them, even in the limit of infinitely many copies. The robustness of the procedure under particle loss is also studied. As a by-product we find bounds on the probability of discriminating by LOCC between the invariant subspaces of total angular momentum N/2 and N/2-1 in a system of N elementary spins.
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"abstract": "We present a procedure to share a secret spatial direction in the absence of\na common reference frame using a multipartite quantum state. The procedure\nguarantees that the parties can determine the direction if they perform joint\nmeasurements on the state, but fail to do so if they restrict themselves to\nlocal operations and classical communication (LOCC). We calculate the fidelity\nfor joint measurements, give bounds on the fidelity achievable by LOCC, and\nprove that there is a non-vanishing gap between the two of them, even in the\nlimit of infinitely many copies. The robustness of the procedure under particle\nloss is also studied. As a by-product we find bounds on the probability of\ndiscriminating by LOCC between the invariant subspaces of total angular\nmomentum N/2 and N/2-1 in a system of N elementary spins.",
"arxiv_id": "quant-ph/0606165",
"authors": [
"E. Bagan",
"J. Calsamiglia",
"R. Demkowicz-Dobrzanski",
"R. Munoz-Tapia"
],
"categories": [
"quant-ph"
],
"doi": "10.1088/1367-2630/9/8/244",
"journal_ref": "New J. Phys. 9 (2007) 244",
"title": "How to hide a secret direction",
"url": "https://arxiv.org/abs/quant-ph/0606165"
},
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