Experimental determination of entanglement by a projective measurement Walborn, S P; Ribeiro, P H. Souto; Davidovich, L; Mintert, F; Buchleitner, A [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972 (Brazil)]; Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States); Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972 (Brazil); Max-Planck-Institut fuer Physik komplexer Systeme, Noethnitzer Strasse 38, D-01187 Dresden (Germany); Max-Planck-Institut fuer Physik komplexer Systeme, Noethnitzer Strasse 38, D-01187 Dresden (Germany)] 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DEGREES OF FREEDOM; PHOTONS; POLARIZATION; QUANTUM ENTANGLEMENT; QUANTUM MECHANICS We describe a method in which the entanglement of any pure quantum state can be experimentally determined by a simple projective measurement, provided the state is available in a twofold copy. We propose implementations of this approach for various systems and discuss in detail its first experimental realization, which employed twin photons entangled in two degrees of freedom, prepared in identical polarization and momentum states. We analyze the effect of errors due to imperfect state preparation. United States 2007-03-15 English Journal Article Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.75.032338; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA) Medium: X; Size: page(s) 032338-032338.9 https://doi.org/10.1103/PHYSREVA.75.032338 [] 3 75 Journal ID: ISSN 1050-2947; PLRAAN; TRN: US07A8512011035 INIS 2010-06-03 20982284