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We present exact soliton solutions of anti-self-dual Yang-Mills equations for G=GL(N) on noncommutative Euclidean spaces in four-dimension by using the Darboux transformations. Generated solutions are represented by quasideterminants of Wronski matrices in compact forms. We give special one-soliton solutions for G=GL(2) whose energy density can be real-valued. We find that the soliton solutions are the same as the commutative ones and can be interpreted as one-domain walls in four-dimension. Scattering processes of the multi-soliton solutions are also discussed., Comment: 20 pages; Jonathan Nimmo sadly passed away on 20 June 2017. We owe section 4 to his unpublished note; v2: minor changes, comments added, references added; version to appear in Special Issue of Journal of Physics A on Integrable Physics and its Connections with Special Functions and Combinatorics

The supersymmetric properties of a charged planar Dirac oscillator coupling to a uniform perpendicular magnetic field are studied. We find that there is an N = 2 supersymmetric structure in both commutative and noncommutative cases. We construct the generators of the supersymmetric algebras explicitly and show that the generators of the supersymmetric algebras can be mapped onto ones which only contain the left or right-handed chiral phonons by unitary transformations.

Quantum homogeneous spaces are noncommutative spaces with quantum group covariance. Their semiclassical counterparts are Poisson homogeneous spaces, which are quotient manifolds of Lie groups $M=G/H$ equipped with an additional Poisson structure $\pi$ which is compatible with a Poisson-Lie structure $\Pi$ on $G$. Since the infinitesimal version of $\Pi$ defines a unique Lie bialgebra structure $\delta$ on the Lie algebra $\frak g=\mbox{Lie}(G)$, we exploit the idea of Lie bialgebra duality in order to study the notion of complementary dual homogeneous space $M^\perp=G^\ast/H^\perp$ of a given homogeneous space $M$ with respect to a coisotropic Lie bialgebra. Then, by considering the natural notions of reductive and symmetric homogeneous spaces, we extend these concepts to $M^\perp$ thus showing that an even richer duality framework between $M$ and $M^\perp$ arises from them. In order to analyse physical implications of these notions, the case of $M$ being a Minkowski or (Anti-) de Sitter Poisson homogeneous spacetime is fully studied, and the corresponding complementary dual reductive and symmetric spaces $M^\perp$ are explicitly constructed in the case of the well-known $\kappa$-deformation, where the cosmological constant $\Lambda$ is introduced as an explicit parameter in order to describe all Lorentzian spaces simultaneously. In particular, the fact that $M^\perp$ is a reductive space is shown to provide a natural condition for the representation theory of the quantum analogue of $M$ that ensures the existence of physically meaningful uncertainty relations between the noncommutative spacetime coordinates. Finally, despite these dual spaces $M^\perp$ are not endowed in general with a $G^\ast$-invariant metric, we show that their geometry can be described by making use of $K$-structures., Comment: 27 pages

It was pointed out by Ezra Newman in the sixties that an imaginary shift of the coordinate in purely classical equations leads to the purely quantum mechanical gyromagnetic ratio g = 2. Newman puzzled about it for decades and finally could not explain this enigmatic finding. The author, Dr. B G Sidharth, Director, B M Birla Science Centre, Hyderabad, has been working on this for a few decades and has concluded the following: 1. The explanation lies at very small scales where the square of the Compton scale is retained and 2. When a complex coordinate is generalized to three dimensions, as Sachs had pointed out we end up with a four dimensional space, which moreover has a Minkowski invariant thrown in. On a further analysis the author noted that in this quaternionic description the spacetime is rather different to the simple Minkowski spacetime. To put it pictorially the former resembles the curly spiral binding while the latter is more like the smooth paper. The author also concluded that this was the reason why despite a century of efforts Einstein’s gravitation could not be reconciled with particle physics. Moving on we consider the second order representation of the quaternions in terms of the 2 × 2 Pauli matrices. This time the line element will be given by σ(i)xi. We get again an invariant but unlike in the 4 × 4 matrix consideration, this time there is no invariance under the reflection symmetry. We consider the different situations like neutrinos, noncommutative geometry and two dimensional surfaces like graphene where this latter case applies.

This paper studies the conductance on the universal homology covering space $Z$ of 2D orbifolds in a strong magnetic field, thereby removing the integrality constraint on the magnetic field in earlier works in the literature. We consider a natural Landau Hamiltonian on $Z$ and show that its low-lying spectrum consists of a finite number of isolated points. We calculate the von Neumann degree of the associated holomorphic spectral orbibundles when the magnetic field $B$ is large, and obtain fractional quantum numbers as the conductance., Comment: 19 pp. Added more references and explanation

We present a new, exact, solution of regular Schwarzschild black hole by introducing an anisotropic perfect fluid inspired by noncommutative geometry. The obtained solution is interpolated between two quantities which are the de Sitter space-time at little distance and the regular Schwarzschild geometry at extensive extent. The consequence of noncommutative geometry is that it alters the thermodynamical characteristics of the black hole. Hawking temperature is calculated and its graphical study affirms striking features with reference to the alteration of the Hawkins temperature with the petty radius of the black hole.

We study noncommutative deformations of the wave equation in curved backgrounds and discuss the modification of the dispersion relations due to noncommutativity combined with curvature of spacetime. Our noncommutative differential geometry approach is based on Drinfeld twist deformation, and can be implemented for any twist and any curved background. We discuss in detail the Jordanian twist $-$giving $\kappa$-Minkowski spacetime in flat space$-$ in the presence of a Friedman-Lema\^{i}tre-Robertson-Walker (FLRW) cosmological background. We obtain a new expression for the variation of the speed of light, depending linearly on the ratio $E_{ph}/E_{LV}$ (photon energy / Lorentz violation scale), but also linearly on the cosmological time, the Hubble parameter and inversely proportional to the scale factor., Comment: 20 pages. New version: 23 pages, added 4-dim. dispersion relations and numerical estimates

In this paper, we explore static spherically symmetric charged wormhole solutions in extended teleparallel gravity taking power-law f(T) models. We consider noncommutative geometry under Lorentzian distribution. In order to obtain matter components, we develop field equations using effective energy-momentum tensor for non-diagonal tetrad. We explore solutions by considering various viable power-law f(T) models, which also include teleparallel gravity case. The violation of energy conditions obtain by exotic matter to form wormhole solutions in teleparallel case while, physical acceptable wormhole solutions exist for charged noncommutative wormhole solutions for some cases of power-law models. The effective energy-momentum tensor and charge are responsible for the violation of the energy conditions. Also, we check the equilibrium condition for these solutions. The equilibrium condition meets for the teleparallel case and some power-law solutions while remaining solutions are either in less equilibrium or in disequilibrium situation.

The noncommutative Bianchi I curved space-time vierbeins and spin connections are derived. Moreover, a general Klein-Gordon equation up to the second order of the noncommutativity θ paramter and its solutions are presented. As an application within the quantum field theory approach using Bogoliubov transformations, the von Neumann boson-antiboson pair creation quantum entanglement entropy is studied. It is shown that its behavior is strongly dependent on the value of the noncommutativity θ parameter, k⊥ modes frequencies and the structure of the curved Bianchi I space-time. various discussions of the obtained numerical results are presented.

We fully solve the quantum geometry of Z n as a polygon graph with arbitrary metric square-lengths on the edges, finding a ∗-preserving quantum Levi-Civita connection which is unique for n ≠ 4. As a first application, we numerically compute correlation functions for Euclideanised quantum gravity on Z n for small n. We then study an FLRW model on R × Z n , finding the same expansion rate as for the classical flat FLRW model in 1 + 2 dimensions. We also look at particle creation on R × Z n and find an additional m = 0 adiabatic no particle creation expansion as well as the particle creation spectrum for a smoothed step expansion.

Conjectures of Beilinson-Bloch type predict that the low-degree rational Chow groups of intersections of quadrics are one-dimensional. This conjecture was proved by Otwinowska in [20]. By making use of homological projective duality and the recent theory of (Jacobians of) non-commutative motives, we give an alternative proof of this conjecture in the case of a complete intersection of either two quadrics or three odd-dimensional quadrics. Moreover, we prove that in these cases the unique non-trivial algebraic Jacobian is the middle one. As an application, we make use of Vial's work [26], [27] to describe the rational Chow motives of these complete intersections and show that smooth fibrations into such complete intersections over bases S of small dimension satisfy Murre's conjecture (when dim(S) [less than or equal to] 1), Grothendieck's standard conjecture of Lefschetz type (when dim(S) [less than or equal to] 2), and Hodge's conjecture (when dim(S) [less than or equal to] 3)., National Science Foundation (U.S.) (CAREER Award #1350472), Fundação para a Ciência e a Tecnologia (Portugal) (project grant UID/MAT/00297/2013 (Centro de Matemática e Aplicações))

In this letter, the relativistic oscillators in dimensions in the context of the Magueijo-Smolin (MS) noncommutative model are considered. In order to appreciate the influence of this deformation, the energy eigenvalues and eigenfunctions are determined for both cases for the Klein-Gordon and the Dirac oscillators. Our calculations show however that the energies and wave functions of the relativistic oscillator are modified by the deformation parameter.

We study classical and quantum noncommutative cosmology with a Liouville-type scalar degree of freedom. The noncommutativity is imposed on the minisuperspace variables through a deformation of the Poisson algebra. In this paper, we investigate the effects of noncommutativity of minisuperspace variables on the accelerating behavior of the cosmic scale factor. The probability distribution in noncommutative quantum cosmology is also studied and we propose a novel candidate for interpretation of the probability distribution in terms of noncommutative arguments., 22 pages, 20 figures. final version

The Dirac oscillator in a homogenous magnetic field exhibits a chirality phase transition at a particular (critical) value of the magnetic field. Recently, this system has also been shown to be exactly solvable in the context of noncommutative quantum mechanics featuring the interesting phenomenon of re-entrant phase transitions. In this work we provide a detailed study of the thermodynamics of such quantum phase transitions (both in the standard and in the noncommutative case) within the Maxwell-Boltzmann statistics pointing out that the magnetization has discontinuities at critical values of the magnetic field even at finite temperatures., 10 pages, 8 figures

Fring and al in their paper entitled "Strings from position-dependent noncommutativity" have introduced a new set of noncommutative space commutation relations in two space dimensions. It had been shown that any fundamental objects introduced in this space-space non-commutativity are string-like. Taking this result into account, we generalize the seminal work of Fring and al to the case that there is also a maximal length from position-dependent noncommutativity and minimal momentum arising from generalized versions of Heisenberg's uncertainty relations. The existence of maximal length is related to the presence of an extra, first order term in particle's length that provides the basic difference of our analysis with theirs. This maximal length breaks up the well known singularity problem of space time. We establish different representations of this noncommutative space and finally we study some basic and interesting quantum mechanical systems in these new variables., Comment: 25 pages

In this work we explore the boundary conditions in the Einstein-Hilbert action, by considering a displacement from the Riemannian manifold to an extended one. The latter is characterized by including spinor fields into the quantum geometric description of a noncommutative spacetime. These fields are defined on the background spacetime, emerging from the expectation value of the quantum structure of spacetime generated by matrices that comply with a Clifford algebra. We demonstrate that spinor fields are candidate to describe all known interactions in physics, with gravitation included. In this framework we demonstrate that the cosmological constant $\Lambda$, is originated exclusively by massive fermion fields that would be the primordial components of dark energy, during the inflationary expansion of an universe that describes a de Sitter expansion., Comment: Version accepted in Physica Scripta

A noncommutative gravitational theory constructed by applying Moyal deformation quantization and the Seiberg–Witten map to teleparallel gravity shows that gravity acts repulsively in an extreme region where its quantum effects become prominent. The problems involved with the order of products and the relationship between the metric and the Moyal product can be solved by assigning their roles, such that the former is responsible for the rule of the inner product and the latter is in charge of tensor and field noncommutativity. As a result, it is found that the cosmic evolution of the very early stage of the universe was modified as if the noncommutative effect works similarly to a cosmological constant. Furthermore it was clarified that the degree of gravitational redshift of a spherically symmetric space with central mass becomes smaller, which means the attractive force is effectively weakened. Such consequences indicate that in the noncommutative spacetime, the gravitational interaction is softened compared to the classical gravity.

Magnetohydrodynamics (MHD) describes the behavior of a charged fluid in a strong magnetic field. One way to analyze noncommutativity in MHD is by considering the result of an eternal magnetic field on noncommutative (NC) photon dynamics. In this paper we have introduced a new MHD Lagrangian and we have obtained the Navier-Stokes MHD equation. We have constructed a NC algebra for the dynamical MHD variables and analyzed the mechanical energy variation rate together with the coupling between the vortex and magnetic field. We have calculated the rate of variation of circulation and analyzed each term. We have seen that these terms are connected to noncommutativity which can act as a source of vorticity.

The presumption that Hawking radiations are thermally distributed can be considered to result from their entanglement with the internal degrees of freedom for a black hole. This leads to the "firewall" paradox if unitary evolution continues into Page's time when a black hole evaporates away half of its initial entropy. However, if the interior of a black hole houses sufficient degrees of freedom to maintain entanglement with the outside at all times, unitarity can be preserved during the complete radiation process and no firewall will be required. This paper proposes a scenario that rescinds firewall by introducing the concept of volume for a black hole. Based on the operational definition by Christodoulou and Rovelli [1], we show that the volume and its associated entropy for a collapsed black hole diverges if the final evaporation stage is treated using noncommutative space. This implicates the interior of a black hole possesses adequate space to store information for a black hole of any mass, like the inside of a "magician's bag".

The mechanism of obtaining the fractional angular momentum by employing a trapped atom which possesses a permanent magnetic dipole moment in the background of two electric fields is reconsidered by using an alternative method. Then, we generalize this model to a noncommutative plane. We show that there are two different mechanisms, which include cooling down the atom to the negligibly small kinetic energy and modulating the density of electric charges to the critical value to get the fractional angular momentum theoretically.

The charged Dirac oscillator on a noncommutative plane coupling to a uniform perpendicular magnetic held is studied in this paper. We map the noncommutative plane to a commutative one by means of Bopp shift and study this problem on the commutative plane. We find that this model can be mapped onto a quantum optics model which contains Anti—Jaynes—Cummings (AJC) or Jaynes—Cummings (JC) interactions when a dimensionless parameter ζ (which is the function of the intensity of the magnetic held) takes values in different regimes. Furthermore, this model behaves as experiencing a chirality quantum phase transition when the dimensionless parameter ζ approaches the critical point. Several evidences of the chirality quantum phase transition are presented. We also study the non-relativistic limit of this model and find that a similar chirality quantum phase transition takes place in its non-relativistic limit.

From the inspection of noncommutative quantum mechanics, we obtain an approximate equivalent relation for the energy dependence of the Planck constant in the noncommutative space, which means a minimal length of the space. We find that this relation is reasonable and it can inherit the main properties of the noncommutative space. Based on this relation, we derive the modified Klein—Gordon equation and Dirac equation. We investigate the scalar field and ϕ4 model and then quantum electrodynamics in our theory, and derive the corresponding Feynman rules. These results may be considered as reasonable approximations to those of noncommutative quantum field theory. Our theory also shows a connection between the space with a minimal length and the noncommutative space.

The LHC measurements of the differential cross section of the Drell-Yan process is used to constrain the noncommutative space-time (NCST) phase space. A $\chi^2$ method is utilized to exclude the part of the parameters space which is not consistent with the LHC measurements. Depending on other NCST parameters, the scale can be pushed up to $\Lambda_{NC} > 655$ GeV. The effect of other parameters is also investigated. To our knowledge, it is the first time that a detailed statistical analysis is performed to compare the NCST results with the Hadron Collider measurements., Comment: 11 pages, 6 figures

The single neutral spin-half particle with electric dipole moment and magnetic dipole moment moving in an external electromagnetic field is studied. The Aharonov-Casher effect and He-McKellar-Wilkens effect are emphatically discussed in noncommutative (NC) space with minimal length. The energy eigenvalues of the systems are obtained exactly in terms of the Jacobi polynomials. Additionally, a special case is discussed and the related energy spectra are plotted.

In this article we provide three new twist-deformed Newtonian Schwarzschild-(Anti-)de Sitter models. They are defined on the Lie-algebraically as well as on the canonically noncommutative space-times respectively. Particularly we find the corresponding Hamiltonian functions and the proper equations of motion. The relations between the models are discussed as well., Comment: 15 pages, Latex source

The present day gravitational wave (GW) detectors strive to detect the length variation $\delta L = h L$, which, owing to the smallness of the metric perturbation $\sim h$, is an extremely small length $\mathcal{O} \sim 10^{-18} - 10^{-21}$ meter. The recently proposed noncommutative structure of space has a characteristic length-scale $\sqrt{\theta}$ which has an estimated upper-bound in similar length-scale range. We therefore propose that GW data can be used as an effective probe of noncommutative structure of space and demonstrate how spatial noncommutativity modifies the responding frequency of the resonant mass detectors of GW and also the corresponding probabilities of GW induced transitions that the phonon modes of the resonant mass detectors undergo. In this paper we present the complete perturbative calculation involving both time-independent and time-dependent perturbation terms in the Hamiltonian., Comment: 11 pages Latex, comments are welcome

Time evolution of modes of density contrast, in particular the growing modes, dictate the structure formation in Universe. In this paper we explicitly show how (spatial) Non-Commutativity (NC) can affect the behavior of the modes, that is we compute NC corrected power law profiles of the density contrast modes. We develop a generalized fluid model that lives in NC space. The dynamical equations of fluid, namely the continuity and Euler equations receive NC contributions. When mapped to comoving coordinates these generate the NC extended versions of continuity and Friedmann equations for cosmology. Introducing cosmological perturbations finally yield the NC corrected evolution of density contrast modes. The construction of the NC fluid model from first principles and development of the formal aspects of its Hamiltonian formulation have been presented in the first part., Revised version, 21 pages, 2 figures, New section added, Accepted in JCAP

We study the Klein—Gordon oscillator in commutative, noncommutative space, and phase space with psudoharmonic potential under magnetic field hence the other choice is studying the Klein—Gordon equation oscillator in the absence of magnetic field. In this work, we obtain energy spectrum and wave function in different situations by NU method so we show our results in tables.

Commutators of Pfaffians associated with the orthogonal algebra are found in skew-symmetric and root realizations of . A generating function of Pfaffians is proved to satisfy the reflection equation. A relation between Pfaffians in skew-symmetric and root realizations of is established. Using these results we construct an integrable equation of Knizhnik-Zamolodchikov type using the Capelli central elements in , which are sums of squares of the considered Pfaffians. A classical limit of the obtained Knizhnik-Zamolodchikov type equation turns out to be a very specific system of equations of isomonodromic deformations. Bibliography: 18 titles.

We construct a noncommutative (Grassmann) extension of the well known Adler Yang-Baxter map. It satisfies the Yang-Baxter equation, it is reversible and birational. Our extension preserves all the properties of the original map except the involutivity., Revised version: Small paragraph added to the introduction, and some other minor changes

In this paper, we introduce the reduced matrix in kq representation and provide the reduced matrix elements of a projection operator on the rational noncommutative orbifold T2/Z4. we give the closed form for the projector by Jacobi elliptical functions. Since projectors correspond to soliton solutions of the field theory on the noncommutative orbifold, we thus present a corresponding soliton solution.

Solutions of a noncommutative nonisospectral Kadomtsev-Petviashvili equation are given in terms of quasiwronskian and quasigrammian respectively. These solutions are verified by direct substitutions. Dynamics of some obtained solutions are illustrated.

In this work, we study the relativistic oscillators in a noncommutative space and in a magnetic field. It is shown that the effect of the magnetic field may compete with that of the noncommutative space and that is able to vanish the effect of the noncommutative space.

In this paper, applying the method of coordinate coherent states to describe a noncommutative model of Vaidya black holes leads to an exact (t — r) dependence of solution in terms of the noncommutative parameter σ. In this setup, there is no black hole remnant at long times.

First we calculate the Wigner phase-space distribution function for the Klein—Gordan Landau problem on a commmutative space. Then we study the modifications introduced by the coordinate-coordinate noncommuting and momentum-momentum noncommuting, namely, by using a generalized Bopp's shift method we construct the Wigner function for the Klein—Gordan Landau problem both on a noncommutative space (NCS) and a noncommutative phase space (NCPS).

The Drinfeld-Manin construction of U(N) instanton is reformulated in the ADHM formulism, which gives explicit general solutions of the ADHM constraints for U(N) (N>=2k-1) k-instantons. For the N, 17 pages, LaTeX, references added, mailing address added, clarifications added

The Yang-Baxter (YB) deformation is a systematic way of performibg integrable deformations of two-dimensional symmetric non-linear sigma models. The deformations can be labeled by classical $r$-matrices satisfying the classical YB equation. This YB deformation is also applicable to type IIB superstring theory defined on $\mathrm{AdS}_5\times S^5$. In this case, a simple class of YB deformation is associated with TsT transformations of string backgrounds. The data of this transformation is encoded in an antisymmetric bi-vector $\Theta$ (which is often called $\beta$ field or non-commutativity parameter). In this article, we give a simple recipe for obtaining the explicit expression for the Killing spinors of the TsT transformed background starting from $\Theta$. We moreover discuss the M-theory equivalent of the TsT transformation, allowing us to also give Killing spinors of 11-dimensional backgrounds. We discuss examples of TsT transformed backgrounds starting from flat space, $\mathrm{AdS}_{5}\times S^5$ and $\mathrm{AdS}_{7}\times S^4$. We find that in this way we can relate the $\Omega$-deformation to YB deformations., Comment: 50 pages, typos corrected. Version published in J.Phys.A