Electromagnetic superconductivity of vacuum induced by strong magnetic field: Numerical evidence in lattice gauge theory

Using numerical simulations of quenched SU(2)$\mathit{SU}(2)$ gauge theory we demonstrate that an external magnetic field leads to spontaneous generation of quark condensates with quantum numbers of electrically charged ρ   mesons if the strength of the magnetic field exceeds the critical value e_Bc=0.927(77) GeV²$e{B}_c=0.927(77){\text{GeV}}^2$ or _Bc=(1.56±0.13)⋅10¹⁶ Tesla$B_c=(1.56\pm 0.13)\cdot {10}^{16}\text{Tesla}$. The condensation of the charged ρ mesons in strong magnetic field is a key feature of the magnetic-field-induced electromagnetic superconductivity of the vacuum.     

Supersymmetric grand unification with light color-triplet

We construct a natural model of the supersymmetric SU(6)$\mathit{SU}(6)$ unification, in which the symmetry breaking, down to the standard model gauge group, results in the number of pseudo-Nambu–Goldstone superfields with interesting properties. Namely, besides the Higgs doublet–antidoublet pair which is responsible for the electroweak phase transition, the Nambu–Goldstone sector consists of multiplets in the anti- and fundamental representations of SU(5)$\mathit{SU}(5)$. While being strictly massless in the supersymmetric limit, they acquire the weak scale masses as a result of its breaking. The color-triplet components of this light sector could, in principle, mediate an unacceptably fast proton decay; however, because of the natural TeV/_MGUT$\text{TeV}/M_{\mathrm{GUT}}$ suppression of the Yukawa couplings to the light quarks and leptons, their existence is compatible with the experimental bound on proton lifetime. This suppression is made further interesting, since it results in the lifetime, of the lightest of the above-mentioned colored particles from 1 s to 1 day$1\text{day}$, long enough for it to appear stable in the detector. Furthermore, we argue that the accommodation of the color-triplet pseudo-Nambu–Goldstones, without fine-tuning or contradicting observations, implies SU(6)$\mathit{SU}(6)$ unification.     

On DBI Textures with generalized Hopf fibration

In this Letter we show numerical existence of O(4)$O(4)$ Dirac–Born–Infeld (DBI) Textures living in (N+1)$(N+1)$ dimensional spacetime. These defects are characterized by S^N→S³$S^N\to S^3$ mapping, generalizing the well-known Hopf fibration into _πN(S³)${\pi }_N(S^3)$, for all N>3$N>3$. The nonlinear nature of DBI kinetic term provides stability against size perturbation and thus renders the defects having natural scale.     

Isomer-tagged differential-plunger measurements in proton-unbound Ho

The lifetime of an excited state above a weakly populated isomer in the proton-unbound odd–odd nucleus ¹⁴⁴Ho has been measured using the recoil distance Doppler shift method. This measurement represents the first differential-plunger lifetime measurement to utilize recoil-isomer tagging. The first excited Iπ=(¹⁰⁺)$I^{\pi }=({10}^{+})$ state above the two-quasiparticle πh_11/2⊗νh_11/2(⁸⁺)$\pi h_{11/2}\otimes \nu h_{11/2}(8^{+})$ isomer was determined to have a lifetime of τ=6(1) ps$\tau =6(1)\text{ps}$. Potential energy surface calculations, based on the configuration-constrained blocking method, predict the isomeric state to have γ  -soft triaxial-nuclear shape with |γ|≈24°$|\gamma |\approx 24\text{°}$. The lifetime of the (¹⁰⁺)$({10}^{+})$ state can be understood from these calculations if there is a degree of rotational alignment in this band, with the K value being lower than the bandhead spin. However, the validity of the K quantum number with large predicted triaxiality and gamma softness requires further theoretical study.     

Determination of strange sea distributions from νN deep inelastic scattering

We present an analysis of the nucleon strange sea extracted from a global Parton Distribution Function fit including the neutrino and anti-neutrino dimuon data by the CCFR and NuTeV Collaborations, the inclusive charged lepton–nucleon Deep Inelastic Scattering and Drell–Yan data. The (anti-)neutrino induced dimuon analysis is constrained by the semileptonic charmed-hadron branching ratio Bμ=(8.8±0.5)%$B_{\mu }=(8.8\pm 0.5)\mathrm{\%}$, determined from the inclusive charmed hadron measurements performed by the FNAL-E531 and CHORUS neutrino emulsion experiments. Our analysis yields a strange sea suppression factor κ(20 GeV²)=0.62±0.04(exp.)±0.03(QCD)$\kappa (20{\text{GeV}}^2)=0.62\pm 0.04(\text{exp.})\pm 0.03(\text{QCD})$, the most precise value available, an x-distribution of total strange sea that is slightly softer than the non-strange sea, and an asymmetry between strange and anti-strange quark distributions consistent with zero (integrated over x   it is equal to S⁻(20 GeV²)=0.0013±0.0009(exp.)±0.0002(QCD)$S^{-}(20{\text{GeV}}^2)=0.0013\pm 0.0009(\text{exp.})\pm 0.0002(\text{QCD})$).     

Search for lepton flavor violation in supersymmetric models via meson decays

Considering the constraints from the experimental data on μ→eγ$\mu \to e\gamma$, μ→3e$\mu \to 3e$, μ–e$\mu \text{–}e$ conversion, etc., we analyze the lepton flavor violating decays ?(J/Ψ,?(1S))→e⁺μ⁻(μ⁺τ⁻)$?(J/\Psi ,?(1S))\to e^{+}{\mu }^{-}({\mu }^{+}{\tau }^{-})$ in the scenarios of the minimal supersymmetric extensions of Standard Model with seesaw mechanism. Numerically, there is parameter space that the LFV processes of J/Ψ(?)→μ⁺τ⁻$J/\Psi (?)\to {\mu }^{+}{\tau }^{-}$ can reach the upper experimental bounds, meanwhile the theoretical predictions on μ→eγ$\mu \to e\gamma$, μ→3e$\mu \to 3e$, μ–e$\mu \text{–}e$ conversion satisfy the present experimental bounds. For searching of new physics, lepton flavor violating processes J/Ψ(?)→μ⁺τ⁻$J/\Psi (?)\to {\mu }^{+}{\tau }^{-}$ may be more promising and effective channels.     

Universal extra dimensions on real projective plane

We propose a six-dimensional Universal Extra Dimensions (UED) model compactified on a real projective plane RP²${\mathit{RP}}^2$, a two-sphere with its antipodal points being identified. We utilize the Randjbar-Daemi–Salam–Strathdee spontaneous sphere compactification with a monopole configuration of an extra UX₍₁₎$U{(1)}_X$ gauge field that leads to a spontaneous radius stabilization. Unlike the sphere and the S²/Z₂$S^2/Z_2$ orbifold compactifications, the massless UX₍₁₎$U{(1)}_X$ gauge boson is safely projected out. We show how a compactification on a non-orientable manifold results in a chiral four-dimensional gauge theory by utilizing 6D chiral gauge and Yukawa interactions. The resultant Kaluza–Klein mass spectra are distinct from the ordinary UED models compactified on torus. We briefly comment on the anomaly cancellation and also on a possible dark matter candidate in our model.     

Fixed point resolution in extensions of permutation orbifolds

We determine the simple currents and fixed points of the orbifold theory CFT⊗CFT/Z₂$\mathit{CFT}\otimes \mathit{CFT}/{\mathbb{Z}}_2$, given the simple currents and fixed point of the original CFT  . We see in detail how this works for the SUk₍₂₎$\mathit{SU}{(2)}_k$ WZW model, focusing on the field content (i.e. h  -spectrum of the primary fields) of the theory. We also look at the fixed point resolution of the simple current extended orbifold theory and determine the SJ$S^J$ matrices associated to each simple current for SU₂₍₂₎$\mathit{SU}{(2)}_2$ and for the B_1(n)$B{(n)}_1$ and D_1(n)$D{(n)}_1$ series.     

Decaying hidden gaugino as a source of PAMELA/ATIC anomalies

We study a scenario that a U(1)$\mathrm{U}(1)$ hidden gaugino constitutes the dark matter in the Universe and decays into a lepton and slepton pair through a mixing with a U_(1)B–_L$\mathrm{U}{(1)}_{\mathrm{B}\text{–}\mathrm{L}}$ gaugino. We find that the dark-matter decay can account for the recent PAMELA and ATIC anomalies in the cosmic-ray positrons and electrons without an overproduction of antiprotons.     

Mechanical analogues of spin Hamiltonians and dynamics

Bloch et al. mapped the precession of the spin-half in a magnetic field of variable magnitude and direction to the rotations of a rigid sphere rolling on a curved surface utilizing SU(2)–SO(3)$\mathit{SU}(2)\text{–}\mathit{SO}(3)$ isomorphism. This formalism is extended to study the behaviour of spin–orbit interactions and the mechanical analogy for Rashba–Dresselhauss spin–orbit interaction in two dimensions is presented by making its spin states isomorphic to the rotations of a rigid sphere rolling on a ring. The change in phase of spin is represented by the angle of rotation of sphere after a complete revolution. In order to develop the mechanical analogy for the spin filter, we find that perfect spin filtration of down spin makes the sphere to rotate at some unique angles and the perfect spin filtration of up spin causes the rotations with certain discrete frequencies.     

The Harari–Shupe preon model and nonrelativistic quantum phase space

We propose that the whole algebraic structure of the Harari–Shupe rishon model originates via a Dirac-like linearization of quadratic form x²+p²${\mathbf{x}}^2+{\mathbf{p}}^2$, with position and momentum satisfying standard commutation relations. The scheme does not invoke the concept of preons as spin-1/2 subparticles, thus evading the problem of preon confinement, while fully explaining all symmetries emboded in the Harari–Shupe model. Furthermore, the concept of quark colour is naturally linked to the ordering of rishons. Our scheme leads to group U(1)⊗SU(3)$U(1)\otimes \mathit{SU}(3)$ combined with SU(2)$\mathit{SU}(2)$, with two of the SU(2)$\mathit{SU}(2)$ generators not commuting with reflections. An interpretation of intra-generation quark–lepton transformations in terms of genuine rotations and reflections in phase space is proposed.     

Tensor decomposition in electronic structure calculations on 3D Cartesian grids

In this paper, we investigate a novel approach based on the combination of Tucker-type and canonical tensor decomposition techniques for the efficient numerical approximation of functions and operators in electronic structure calculations. In particular, we study applicability of tensor approximations for the numerical solution of Hartree–Fock and Kohn–Sham equations on 3D Cartesian grids. We show that the orthogonal Tucker-type tensor approximation of electron density and Hartree potential of simple molecules leads to low tensor rank representations. This enables an efficient tensor-product convolution scheme for the computation of the Hartree potential using a collocation-type approximation via piecewise constant basis functions on a uniform n×n×n$n\times n\times n$ grid. Combined with the Richardson extrapolation, our approach exhibits O(h³)$O(h^3)$ convergence in the grid-size h=O(n^-1)$h=O(n^{-1})$. Moreover, this requires O(3rn+r³)$O(3\mathit{rn}+r^3)$ storage, where r   denotes the Tucker rank of the electron density with r=O(logn)$r=O(\log n)$, almost uniformly in n  . For example, calculations of the Coulomb matrix and the Hartree–Fock energy for the CH₄${\text{CH}}_4$ molecule, with a pseudopotential on the C atom, achieved accuracies of the order of 10^-6${10}^{-6}$ hartree with a grid-size n of several hundreds. Since the tensor-product convolution in 3D is performed via 1D convolution transforms, our scheme markedly outperforms the 3D-FFT in both the computing time and storage requirements.