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The symmetrized product for quantum mechanical observables is defined. It is seen as consisting of the ordinary multiplication and the application of the superoperator that orders the operators of coordinate and momentum. This superoperator…

Quantum Physics · Physics 2007-05-23 S. Prvanovic , Z. Maric

A generalized Noether's theorem and the operational determination of a physical geometry in quantum physics are used to motivate a quantum geometry consisting of relations between quantum states that are defined by a universal group. Making…

Quantum Physics · Physics 2007-05-23 Jeeva Anandan

A Lagrangian formalism for variational second-order delay ordinary differential equations (DODEs) is developed. The Noether operator identity for a DODE is established, which relates the invariance of a Lagrangian function with the…

Mathematical Physics · Physics 2023-03-17 V. A. Dorodnitsyn , R. V. Kozlov , S. V. Meleshko

We offer a clear physical explanation for the emergence of the quantum operator formalism, by revisiting the role of the vacuum field in quantum mechanics. The vacuum or random zero-point radiation field has been shown previously, using the…

Quantum Physics · Physics 2020-11-25 Ana María Cetto , Luis de la Peña , Andrea Valdés-Hernández

Generally-unbounded infinitesimal generators are studied in the context of operator topology. Beginning with the definition of seminorm, the concept of locally convex topological vector space is introduced as well as the concept of…

Functional Analysis · Mathematics 2020-06-09 Yoritaka Iwata

We analyze a class of quantum operations based on a geometrical representation of $d-$level quantum system (or qudit for short). A sufficient and necessary condition of complete positivity, expressed in terms of the quantum Fourier…

Quantum Physics · Physics 2009-11-10 Runyao Duan , Zhengfeng Ji , Yuan Feng , Mingsheng Ying

At the primary level of reality as described by quantum field theory, a fundamental particle like an electron represents a stable, discrete, propagating excited state of its underlying quantum field. QFT also tells us that the lowest vacuum…

General Physics · Physics 2014-04-03 Mani Bhaumik

We discuss the notion about physical quantities as having values represented by real numbers, and its limiting to describe nature to be understood in relation to our appreciation that the quantum theory is a better theory of natural…

Quantum Physics · Physics 2021-01-13 Otto C. W. Kong , Wei-Yin Liu

Crystal tensor operators, which tranform under U_q->0(sl(2)), in analogous way as the vectors of the crystal basis, are introduced. The Wigner-Eckart theorem for the crystal tensor is defined: the selection rules depend on the initial state…

Quantum Algebra · Mathematics 2007-05-23 Vincenzo Marotta , Antonino Sciarrino

A quantum scalar field theory with spacetime-dependent coupling is studied. Surprisingly, while translation invariance is explicitly broken in the classical theory, momentum conservation is recovered at the quantum level for some specific…

High Energy Physics - Theory · Physics 2014-01-29 Gianluca Calcagni , Giuseppe Nardelli

Quantization of free Dirac fields is formulated in terms of a reducible representation of CAR. Similarly to the bosonic case we arrive at field operators which are indeed operators and not operator valued distributions. Observables such as…

Quantum Physics · Physics 2007-05-23 Marek Czachor

It is shown that q-deformed quantum mechanics (systems with q-deformed Heisenberg commutation relations) can be interpreted as an ordinary quantum mechanics on Kaehler manifolds, or as a quantum theory with second (or first)- class…

Quantum Physics · Physics 2009-10-30 Sergei V. Shabanov

The position operator (defined within the Schroedinger representation in the standard way) becomes meaningless when periodic boundary conditions are adopted for the wavefunction, as usual in condensed matter physics. We show how to define…

Materials Science · Physics 2009-10-30 R. Resta

We define a "quantum relation" on a von Neumann algebra M \subset B(H) to be a weak* closed operator bimodule over its commutant M'. Although this definition is framed in terms of a particular representation of M, it is effectively…

Operator Algebras · Mathematics 2010-05-04 Nik Weaver

A number of arguments purport to show that quantum field theory cannot be given an interpretation in terms of localizable particles. We show, in light of such arguments, that the classical $\hbar\to 0$ limit can aid our understanding of the…

History and Philosophy of Physics · Physics 2021-04-15 Benjamin H. Feintzeig , Jonah Librande , Rory Soiffer

A general theory is presented of quantum mechanics of singular, non-autonomous, higher derivative systems. Within that general theory, $n$-th order and $m$-th order Lagrangians are shown to be quantum mechanically equivalent if their…

High Energy Physics - Theory · Physics 2016-09-06 Yasuhito Kaminaga

Some consequences of promoting the object of noncommutativity ${\mathbf \theta}^{ij}$ to an operator in Hilbert space are explored. Consequently, a consistent algebra involving the enlarged set of canonical operators is obtained, which…

High Energy Physics - Theory · Physics 2008-11-26 Ricardo Amorim

A didatic approach of the Noether's theorem in classical mechanics is derived and used to obtain the laws of conservation.

Classical Physics · Physics 2007-05-23 Rubens de Melo Marinho

Quantum physics can only make statistical predictions about possible measurement outcomes, and these predictions originate from an operator algebra that is fundamentally different from the conventional definition of probability as a…

Quantum Physics · Physics 2020-06-11 Holger F. Hofmann

Linear and angular momenta of a soliton in a ferromagnet are commonly derived through the application of Noether's theorem. We show that these quantities exhibit unphysical behavior: they depend on the choice of a gauge potential in the…

Mesoscale and Nanoscale Physics · Physics 2015-10-12 Oleg Tchernyshyov
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