Spin squeezing, entanglement and correlations

Sirsi, S. (2004) Spin squeezing, entanglement and correlations. Journal of Optics B Quantum and Semiclassical Optics, 6 (11). pp. 437-443. ISSN 1464-4266

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Abstract

Spin-s assemblies are classified into two mutually exclusive classes: oriented and non-oriented systems. The density matrix rho, describing oriented systems, can assume diagonal form in the angular momentum basis \textbackslashsm> (in = -s (. . .) +s) defined with respect to the axis of quantization, whereas the eigenstates of rho for the non-oriented assembly cannot all be identified with \textbackslashsm> states. A new scheme for constructing a mixed, non-oriented spin-s state using s (2s + 1) spinors all pointing in different directions in space and 2s weights is discussed. Such a construction takes its inspiration from Schwinger's idea of realizing an \textbackslashsm> state as being made up of (s + m) `up' spinors and (s - m) `down' spinors, all defined with respect to a single axis in space. Since the oriented systems are never squeezed, non-oriented spin-1 assemblies which can be prepared in the laboratory with the available NQR technology are examined for signatures of squeezing using our scheme in a frame of reference where the Heisenberg-Robertson uncertainty relation has the same form as the Schrodinger uncertainty relation. It is shown that unlike in the case of the pure spin-1 state where squeezing is synonymous with non-orientedness, a non-oriented spin-l system need not be squeezed and the existence of entanglement is a necessary but not sufficient condition for the system to be squeezed.

Item Type:	Article
Uncontrolled Keywords:	spin polarization; spin squeezing; quantum correlations
Subjects:	D Physical Science > Physics
Divisions:	Yuvaraj college > Physics
Depositing User:	Users 23 not found.
Date Deposited:	04 Sep 2019 09:33
Last Modified:	04 Sep 2019 09:33
URI:	http://eprints.uni-mysore.ac.in/id/eprint/6530

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