Berlin 2014 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 62: Precision measurements and metrology IV
Q 62.3: Talk
Friday, March 21, 2014, 14:45–15:00, DO24 1.101
Multiparticle singlet states and their metrological applications — •Iñigo Urizar-lanz1, Zoltán Zimboras1, Iagoba Apellaniz1, and Géza Tóth1,2,3 — 1Theoretical Physics, The University of the Basque Country, E-48080 Bilbao, Spain — 2IKERBASQUE, Basque Foundation for Science, E-48011 Bilbao, Spain — 3Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
Singlet states are quantum states of vanishing angular momentum. When composing the angular momenta of two spin-j particles, there appears a unique singlet state, however, for an ensemble of N particles there exists a plethora of different types of singlets. We present a partial classification of them, and then focus on the permutationally invariant (PI) ones. Their basic properties and characterization is presented, and some specific PI singlets are studied for metrological applications. In particular, we calculate the maximal achievable accuracy when measuring the gradient of a magnetic field using these states. Moreover, we single out a measurement set-up that saturates the bound given by the quantum Fisher Information.