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Bounds of the minimum evolution time between two distinguishable states of a system can help to assess the maximal speed of quantum computers and communication channels. We study the quantum speed limit time of a composite quantum states in…

Quantum Physics · Physics 2014-09-16 Ying-Jie Zhang , Wei Han , Yun-Jie Xia , Ke-Xia Jiang , Jun-Peng Cao , Heng Fan

The states generated by the two-spin generalization of the two-axis countertwisting Hamiltonian are examined. We analyze the behavior at both short and long timescales, by calculating various quantities such as squeezing, spin expectation…

A recent method of constructing quantum mechanics in noncommutative coordinates, alternative to implying noncommutativity by means of star product is discussed. Within this approach we study Hall effect as well as quantum phases in…

Mathematical Physics · Physics 2010-08-27 O. F. Dayi , B. Yapiskan

We introduce the Gaussian quantum operator representation, using the most general multi-mode Gaussian operator basis. The representation unifies and substantially extends existing phase-space representations of density matrices for Bose…

Quantum Physics · Physics 2009-11-10 Joel F. Corney , Peter D. Drummond

Solid experimental evidence has now been obtained that confirms the violation of Bell's inequality in tests of maximally entangled qubit pairs. This violation is widely interpreted as definitive proof of the impossibility of describing…

Quantum Physics · Physics 2025-10-20 David H. Oaknin

Some properties of Plebanski squeezing operator and squeezed states created with time-dependent quadratic in position and momentum Hamiltonians are reviewed. New type of tomography of quantum states called squeeze tomography is discussed.

Quantum Physics · Physics 2007-05-23 Octavio Castanos , Ramon Lopez-Pena , Margarita A. Man'ko , Vladimir I. Man'ko

Processing quantum information on continuous variables requires a highly nonlinear element in order to attain universality. Noise reduction in processing such quantum information involves the use of a nonlinear phase state as a non-Gaussian…

Quantum Physics · Physics 2019-11-27 Darren W. Moore , Andrey A. Rakhubovsky , Radim Filip

In order to resolve the measurement problem of Quantum Mechanics, non-unitary time evolution has been derived from the unitarity of standard quantum formalism. New wave functions of free and non-free quantum systems follow from Schroedinger…

Quantum Physics · Physics 2007-05-23 Pradip Kumar Chatterjee

First a generalized Bell-inequality for different times and for different quasi-spin states is developed. We focus on special quasi-spin eigenstates and times. The inequality based on a local realistic theory is violated by the CP-violating…

High Energy Physics - Phenomenology · Physics 2016-09-06 B. C. Hiesmayr

We re-visit the generation and evolution of (Bell) nonlocality in hybrid scenarios whose dynamics is determined by the Jaynes-Cummings Hamiltonian, a relevant example of which is the atom-cavity system. Previous approaches evaluate the…

Quantum Physics · Physics 2024-10-15 Alexander Bernal , J. Alberto Casas , Jesus M. Moreno

We show that there are Bell-type inequalities for noncontextual theories that are violated by any quantum state. One of these inequalities between the correlations of compatible measurements is particularly suitable for testing this…

Quantum Physics · Physics 2009-07-28 Adan Cabello

A planar phase space having both position and momentum noncommutativity is defined in a more inclusive setting than that considered elsewhere. The dynamics of a particle in a gravitational quantum well in this space is studied. The use of…

High Energy Physics - Theory · Physics 2008-11-26 Rabin Banerjee , Binayak Dutta Roy , Saurav Samanta

As contrasted with physicists to idolize Bell's theorem and quantum nonlocality, we argue that quantum mechanics (QM), in reality, respects the principles of a macroscopic realism (PMRs). The current QM to tell us that "... the state of a…

Quantum Physics · Physics 2007-09-20 N. L. Chuprikov

We explore the group theoretical underpinning of noncommutative quantum mechanics for a system moving on the two-dimensional plane. We show that the pertinent groups for the system are the two-fold central extension of the Galilei group in…

Mathematical Physics · Physics 2013-03-12 S. Hasibul Hassan Chowdhury , S. Twareque Ali

We provide a detailed analysis of the recently proposed setup for a loophole-free test of Bell inequality using conditionally generated non-Gaussian states of light and balanced homodyning. In the proposed scheme, a two-mode squeezed vacuum…

Quantum Physics · Physics 2009-11-10 R. Garcia-Patron , J. Fiurasek , N. J. Cerf

Temporal Bell inequalities, or Leggett-Garg Inequalities (LGI), are studied for continuous-variable systems placed in a squeezed state. The importance of those systems lies in their broad applicability which allows the description of many…

Quantum Physics · Physics 2021-07-19 Jerome Martin , Vincent Vennin

In view of the increasing importance of non-Gaussian entangled states in quantum information protocols like teleportation and violations of Bell inequalities, the steering of continuous variable non-Gaussian entangled states is…

Quantum Physics · Physics 2014-08-01 Priyanka Chowdhury , Tanumoy Pramanik , A. S. Majumdar , G. S. Agarwal

This thesis focuses on the mathematical description and application of nonlinear cavity optomechanical systems. The first part is concerned with solving the dynamics of the standard nonlinear optomechanical Hamiltonian with an additional…

Quantum Physics · Physics 2020-03-27 Sofia Qvarfort

Squeezing is a nonlinear Gaussian operation that is the key component in construction of other nonlinear Gaussian gates. In our implementation of the squeezing gate, the amount and the orientation of the squeezing can be controlled by an…

We identify the large-$N$ scaling of the metrological quantum gain offered by over-squeezed spin states that are accessible by one-axis-twisting, as a function of the preparation time. We further determine how the scaling is modified by…

Quantum Physics · Physics 2022-02-03 Y. Baamara , A. Sinatra , M. Gessner