caa a22 4500 44588665X CHVBK 20180317145601.0 cr unu---uuuuu 170323e20110801xx s 000 0 eng 10.1007/s11128-010-0206-x doi (NATIONALLICENCE)springer-10.1007/s11128-010-0206-x Quantifying entanglement of two relativistic particles using optimal entanglement witness [Elektronische Daten] [M. Jafarizadeh, M. Mahdian] In a recent paper, it was shown that the projections of a relativistic spin operator (RSO) massive spin-$${\frac{1}{2}}$$ particle on a world-vector which can be in timelike or null tetrad direction are proportional to the helicity or Bargman-Wigner (BW) qubit, respectively. Here we consider Lorentz transformations of two-particle states, which have been constructed both in helicity basis. For convenience, instead of using the superposition of momenta we use only two momentum eigenstates (p 1 and p 2) for each particle. Consequently, in 2D momentum subspace we describe the structure of one particle in terms of the four-qubit system. We present a new approach to quantification of relativistic entanglement based on entanglement witness (EW), which is obtained by a new method of convex optimization. In addition, Lorentz invariance of entanglement using BW qubit is also studied. Springer Science+Business Media, LLC, 2010 Relativistic entanglement nationallicence Entanglement witnesses nationallicence Convex optimization nationallicence Two-spinor nationallicence Jafarizadeh M. Department of Theoretical Physics and Astrophysics, University of Tabriz, 51664, Tabriz, Iran aut Mahdian M. Department of Theoretical Physics and Astrophysics, University of Tabriz, 51664, Tabriz, Iran aut Quantum Information Processing Springer US; http://www.springer-ny.com 10/4(2011-08-01), 501-518 1570-0755 10:4<501 2011 10 11128 https://doi.org/10.1007/s11128-010-0206-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11128-010-0206-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Jafarizadeh M. Department of Theoretical Physics and Astrophysics, University of Tabriz, 51664, Tabriz, Iran aut NATIONALLICENCE 700 1- Mahdian M. Department of Theoretical Physics and Astrophysics, University of Tabriz, 51664, Tabriz, Iran aut NATIONALLICENCE 773 0- Quantum Information Processing Springer US; http://www.springer-ny.com 10/4(2011-08-01), 501-518 1570-0755 10:4<501 2011 10 11128 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer