8,850 research outputs found

    Single-shot quantum measurements sketch quantum many-body states

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    Quantum measurements are our eyes to the quantum systems consisting of a multitude of microscopic degrees of freedom. However, the intrinsic uncertainty of quantum measurements and the exponentially large Hilbert space pose natural barriers to simple interpretations of the measurement outcomes. We propose a nonlinear "measurement energy" based upon the measurement outcomes and an iterative effective-Hamiltonian approach to extract the most probable states (maximum likelihood estimates) in an efficient and general fashion, thus reconciling the non-commuting observables and getting more out of the quantum measurements. We showcase the versatility and accuracy of our perspective on random long-range fermion models and Kitaev quantum spin liquid models, where smoking-gun signatures were lacking. Our study also paves the way towards concepts such as nonlinear-operator Hamiltonian and applications such as parent Hamiltonian reconstruction.Comment: 6 pages, 5 figure

    A γ\gamma-ray Quasi-Periodic modulation in the Blazar PKS 0301−-243?

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    We report a nominally high-confidence γ\gamma-ray quasi-periodic modulation in the blazar PKS 0301−-243. For this target, we analyze its \emph{Fermi}-LAT Pass 8 data covering from 2008 August to 2017 May. Two techniques, i.e., the maximum likelihood optimization and the exposure-weighted aperture photometry, are used to build the γ\gamma-ray light curves. Then both the Lomb-Scargle Periodogram and the Weighted Wavelet Z-transform are applied to the light curves to search for period signals. A quasi-periodicity with a period of 2.1±0.32.1\pm0.3 yr appears at the significance level of ∼5σ\sim5\sigma, although it should be noted that this putative quasi-period variability is seen in a data set barely four times longer. We speculate that this γ\gamma-ray quasi-periodic modulation might be evidence of a binary supermassive black hole.Comment: 9 pages, 8 figures; Accepted for publication in Ap
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