Nonmaximally Entangled States: Production, Characterization, and Utilization

Journal Article · Fri Oct 01 04:00:00 EDT 1999 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.83.3103· OSTI ID:686907

White, A G; Kwiat, P G ^[1]; James, D F ^[2]; Eberhard, P H ^[3]

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1. Physics Division, P-23, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2. Theoretical Division, T-4, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
3. Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)

Using a spontaneous-down-conversion photon source, we produce true nonmaximally entangled states, i.e., without the need for postselection. The degree and phase of entanglement are readily tunable, and are characterized both by a standard analysis using coincidence minima, and by quantum state tomography of the two-photon state. Using the latter, we experimentally reconstruct the reduced density matrix for the polarization. Finally, we use these states to measure the Hardy fraction, obtaining a result that is 122{sigma} from any local-realistic result. {copyright} {ital 1999} {ital The American Physical Society }

• OSTI ID: 686907
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 16 Vol. 83; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
DENSITY MATRIX
INTERFERENCE
PHOTONS
POLARIZATION
QUANTUM MECHANICS
TOMOGRAPHY