Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effect of Wigner rotation on estimating unitary-shift parameter of
  relativistic spin-1/2 particle   We obtain the accuracy limit for estimating the expectation value of the
position of a relativistic particle for an observer moving along one direction
at a constant velocity. We use a specific model of a relativistic spin-1/2
particle described by a gaussian wave function with a spin down in the rest
frame. To derive the state vector of the particle for the moving observer, we
use the Wigner rotation that entangles the spin and the momentum of the
particle. Based on this wave function for the moving frame, we obtain the
symmetric logarithmic derivative (SLD) Cramer-Rao bound that sets the
estimation accuracy limit for an arbitrary moving observer. It is shown that
estimation accuracy decreases monotonically in the velocity of the observer
when the moving observer does not measure the spin degree of freedom. This
implies that the estimation accuracy limit worsens with increasing the
observer's velocity, but it is finite even in the relativistic limit. We derive
the amount of this information loss by the exact calculation of the SLD Fisher
information matrix in an arbitrary moving frame.

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The categories of this paper are: physics
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The categories of this paper are: q-alg
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The categories of this paper are: plasm-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: gr-qc
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The categories of this paper are: econ
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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ph
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The categories of this paper are: eess
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The categories of this paper are: atom-ph
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The categories of this paper are: math-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga