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Consequences of new quantum spin perspective in quantum gravity are far-reaching. Results of this novel perspective in loop quantum gravity, i.e., the modification of the equation of geometrical operators such as the area and the volume…

General Relativity and Quantum Cosmology · Physics 2023-04-11 Rakshit P. Vyas , Mihir J. Joshi

A quantum measurement involves energy exchanges between the system to be measured and the measuring apparatus. Some of them involve energy losses, for example because energy is dissipated into the environment or is spent in recording the…

Quantum Physics · Physics 2025-04-10 Guillermo Perna , Esteban Calzetta

Quantum mechanics postulates that measuring the qubit's wave function results in its collapse, with the recorded discrete outcome designating the particular eigenstate that the qubit collapsed into. We show that this picture breaks down…

As one of the main pillars of quantum technologies, quantum metrology aims to improve measurement precision using techniques from quantum information. The two main strategies to achieve this are the preparation of nonclassical states and…

Quantum Physics · Physics 2025-09-16 Matteo Fadel , Noah Roux , Manuel Gessner

The quantum rotor represents, after the harmonic oscillator, the next obvious quantum system to study the complementary pair of variables: the angular momentum and the unitary shift operator in angular momentum. Proper quantification of…

Quantum Physics · Physics 2024-08-13 Ladislav Mišta , Matouš Mišta , Zdeněk Hradil

We critically analyse and compare various recent thought experiments, performed by Amelino-Camelia, Ng et al., Baez et al., Adler et al., and ourselves, concerning the (thought)experimental accessibility of the Planck scale by space-time…

General Relativity and Quantum Cosmology · Physics 2008-07-24 M. Requardt

Randomized measurements are useful for analyzing quantum systems especially when quantum control is not fully perfect. However, their practical realization typically requires multiple rotations in the complex space due to the adoption of…

Quantum Physics · Physics 2025-08-28 Jin-Min Liang , Satoya Imai , Shuheng Liu , Shao-Ming Fei , Otfried Gühne , Qiongyi He

This paper claims that local space-time curvature can non-trivially contribute to the properties of orbital angular momentum in quantum mechanics. Of key importance is the demonstration that an extended orbital angular momentum operator due…

General Relativity and Quantum Cosmology · Physics 2011-04-28 Dinesh Singh , Nader Mobed

When Alice measures all her spin-$\half$ of a large ensemble of $N$ singlets, all along the same direction $\vec a$, she prepares at a distance an ensemble of spins for Bob which, because of statistical fluctuations, have a magnetic moment…

Quantum Physics · Physics 2017-08-31 Nicolas Gisin

Recent advances in transmission electron microscopy (TEM) have opened the path toward spin resonance spectroscopy with single-spin sensitivity. To assess this potential, we investigate the quantum precision limits for sensing magnetic…

Optical fluorescence imaging is capable of measuring both the spatial and rotational dynamics of single molecules. However, unavoidable measurement noise will result in inaccurate estimates of rotational dynamics, causing a molecule to…

Optics · Physics 2019-05-22 Oumeng Zhang , Matthew D. Lew

The ultimate accuracy as regards controlling a qubit with a coherent field is studied in terms of degradation of the fidelity by employing a fully quantum mechanical treatment. While the fidelity error accompanied by pi/2 pulse control is…

Quantum Physics · Physics 2015-06-12 Kazuhiro Igeta , Nobuyuki Imoto , Masato Koashi

We present a new treatment for the spin of a massive relativistic particle in the context of quantum information based on a physical interpretation of the Wigner rotations, obtaining different results in relation to the previous works. We…

Quantum Physics · Physics 2012-02-28 Pablo L. Saldanha , Vlatko Vedral

An experimental test at the intersection of quantum physics and general relativity is proposed: measurement of relativistic frame dragging and geodetic precession using intrinsic spin of electrons. The behavior of intrinsic spin in…

General Relativity and Quantum Cosmology · Physics 2021-03-02 Pavel Fadeev , Tao Wang , Y. B. Band , Dmitry Budker , Peter W. Graham , Alexander O. Sushkov , Derek F. Jackson Kimball

The concepts of separability, entanglement, spin-squeezing and Heisenberg limit are central in the theory of quantum enhanced metrology. In the current literature, these are well established only in the case of linear interferometers…

Quantum Physics · Physics 2013-05-29 P. Hyllus , L. Pezzé , A. Smerzi

We determine the complete set of generalized spin squeezing inequalities, given in terms of the collective angular momentum components, for particles with an arbitrary spin. They can be used for the experimental detection of entanglement in…

Quantum Physics · Physics 2015-01-27 Giuseppe Vitagliano , Philipp Hyllus , Inigo L. Egusquiza , Geza Toth

Recent progress in observing and manipulating mechanical oscillators at quantum regime provides new opportunities of studying fundamental physics, for example, to search for low energy signatures of quantum gravity. For example, it was…

Quantum Physics · Physics 2019-09-24 P. A. Bushev , J. Bourhill , M. Goryachev , N. Kukharchyk , E. Ivanov , S. Galliou , M. E. Tobar , S. Danilishin

Relativity and quantum mechanics are generalized by considering a finite limit for the smallest measurable distance. The value a of this quantum of length is unknown, but it is a universal constant, like c and h. It depends on the total…

General Physics · Physics 2011-08-25 A. Meessen

Generalized uncertainty principle and breakdown of the spacetime continuum certainly represent two important results derived of various approaches related to quantum gravity and black hole physics near the well-known Planck scale. The…

Quantum Physics · Physics 2011-06-14 Marcelo A Marchiolli , Maurizio Ruzzi

There are fundamental reasons as to why there should exist a reformulation of quantum mechanics which does not refer to a classical spacetime manifold. It follows as a consequence that quantum mechanics as we know it is a limiting case of a…

General Relativity and Quantum Cosmology · Physics 2008-11-26 T. P. Singh