Standard model Higgs field and energy scale of gravity

The effective potential of the Higgs scalar field in the Standard Model may have a second degenerate minimum at an ultrahigh vacuum expectation value. This second minimum then determines, by radiative corrections, the values of the top-quark and Higgs-boson masses at the standard minimum corresponding to the electroweak energy scale. An argument is presented that this ultrahigh vacuum expectation value is proportional to the energy scale of gravity, E _Planck ≡ √?c ⁵/G _N, considered to be characteristic of a spacetime foam. In the context of a simple model, the existence of kink-type wormhole solutions places a lower bound on the ultrahigh vacuum expectation value and this lower bound is of the order of E _Planck.     

Scaling and fragmentation distributions of beam remnants in high Et proton-proton collisions at √s =27.4 GeV

Charged particle trajectories have been reconstructed in pp collisions triggered by transverse energies (E_t) ranging from 1 GeV to 20 GeV. The forward fragmentation function of negative particles in the beam jet is found to scale with E_t in variable x=2p_L/√s−E_t, and the slope is near to that found for small jet triggers in an earlier experiment. Above about E_t=8 GeV, positive particles scale and for 0.5<x<1.0 the ratio of positives to negatives is 1.73±0.2. The forward fragmentation functions at high E_t do not show the behavior expected from the fragmentation of diquarks and are more like that from quarks.Multiplicity and energy flow in various forward polar angle regions are also presented; they are compared to the beam jet predictions of ISAJET and found to be greater at wide angles and less at small.     

Universal temperature corrections to the free energy for the gravitational field

The temperature correction to the free energy of the gravitational field is considered which does not depend on the Planck energy physics. The leading correction may be interpreted in terms of the temperature-dependent effective gravitational constant G_eff. The temperature correction to appears to be valid for all temperatures T?E_Planck. It is universal since it is determined only by the number of fermionic and bosonic fields with masses m?T, does not contain the Planck energy scale E_Planck which determines the gravitational constant at T=0, and does not depend on whether or not the gravitational field obeys the Einstein equations. That is why this universal modification of the free energy for gravitational field can be used to study thermodynamics of quantum systems in condensed matter (such as quantum liquids superfluid ³He and ⁴He), where the effective gravity emerging for fermionic and/or bosonic quasiparticles in the low-energy corner is quite different from the Einstein gravity.     

E11 as E10 representation at low levels

The Lorentzian Kac–Moody algebra E₁₁, obtained by doubly overextending the compact E₈, is decomposed into representations of its canonical hyperbolic E₁₀ subalgebra. Whereas the appearing representations at levels 0 and 1 are known on general grounds, higher level representations can currently only be obtained by recursive methods. We present the results of such an analysis up to height 120 in E₁₁ which comprises representations on the first five levels. The algorithms used are a combination of Weyl orbit methods and standard methods based on the Peterson and Freudenthal formulae. In the appendices we give all multiplicities of E₁₀ occurring up to height 340 and for E₁₁ up to height 240.     

On supersymmetry breaking in superstring theories

We show that non-zero gaugino condensates of several non-abelian gauge groups G₁⊗…⊗G_k∃E₈ in low-energy d=4 superstring E₈⊗E₆ gauge theory can lead to the exponentially small (compared to the Planck scale) supersymmetry breaking scale. The Hosotani mechanism can provide the E₈→G₁⊗…⊗G_k breaking.     

From the Bose-Einstein to fermion condensation

The appearance of the fermion condensation, which can be compared to the Bose-Einstein condensation, in different Fermi liquids is considered; its properties are discussed; and a large amount of experimental evidence in favor of the existence of the fermion condensate (FC) is presented. We show that the appearance of FC is a signature of the fermion condensation quantum phase transition (FCQPT), which separates the regions of normal and strongly correlated liquids. Beyond the FCQPT point, the quasiparticle system is divided into two subsystems, one containing normal quasiparticles and the other, FC, localized at the Fermi level. In the superconducting state, the quasiparticle dispersion in systems with FC can be represented by two straight lines, characterized by effective masses M _FC ^* and M _L ^* and intersecting near the binding energy E₀, which is of the order of the superconducting gap. The same quasiparticle picture and the energy scale E₀ persist in the normal state. We demonstrate that fermion systems with FC have features of a “quantum protectorate” and show that strongly correlated systems with FC, which exhibit large deviations from the Landau Fermi liquid behavior, can be driven into the Landau Fermi liquid by applying a small magnetic field B at low temperatures. Thus, the essence of strongly correlated electron liquids can be controlled by weak magnetic fields. A reentrance into the strongly correlated regime is observed if the magnetic field B decreases to zero, while the effective mass M* diverges as \(M^ * \propto {1 \mathord{\left/ {\vphantom {1 {\sqrt B }}} \right. \kern-\nulldelimiterspace} {\sqrt B }}\). The regime is restored at some temperature \(T^ * \propto \sqrt B \). The behavior of Fermi systems that approach FCQPT from the disordered phase is considered. This behavior can be viewed as a highly correlated one, because the effective mass is large and strongly depends on the density. We expect that FCQPT takes place in trapped Fermi gases and in low-density neutron matter, leading to stabilization of the matter by lowering its ground-state energy. When the system recedes from FCQPT, the effective mass becomes density independent and the system is suited perfectly to be conventional Landau Fermi liquid.     

Supersymmetry breaking and soft terms in M-theory

We investigate gaugino condensation in the framework of the strongly coupled heterotic E₈×E₈ string (M-theory). Supersymmetry is broken in a hidden sector and gravitational interactions induce soft breaking parameters in the observable sector. The resulting soft masses are of order of the gravitino mass. The situation is similar to that in the weakly coupled E₈×E₈ theory with one important difference: we avoid the problem of small gaugino masses which are now comparable to the gravitino mass.     

Survival of charged ρ condensation at high temperature and density

The charged vector ρ mesons in the presence of external magnetic fields at finite temperature T and chemical potential μ have been investigated in the framework of the Nambu-Jona-Lasinio model.We compute the masses of charged ρ mesons numerically as a function of the magnetic field for different values of temperature and chemical potential.The self-energy of the ρ meson contains the quark-loop contribution,i.e.the leading order contribution in 1/N_C expansion.The charged ρ meson mass decreases with the magnetic field and drops to zero at a critical magnetic field eB_c,which indicates that the charged vector meson condensation,i.e.the electromagnetic superconductor can be induced above the critical magnetic field.Surprisingly,it is found that the charged ρ condensation can even survive at high temperature and density.At zero temperature,the critical magnetic field just increases slightly with the chemical potential,which indicates that charged ρ condensation might occur inside compact stars.At zero density,in the temperature range 0.2 — 0.5 GeV,the critical magnetic field for charged ρ condensation is in the range of 0.2 — 0.6 GeV~2,which indicates that a high temperature electromagnetic superconductor might be created at LHC.     

Low energy aspects of superstring theories

The effective theory obtained as low energy limit of theE ₈×E ₈ superstring is analyzed from the phenomenological point of view. The supersymmetry breaking manifests itself in the low energy sector only after the radiative corrections involving the goldstino field have been taken into account. A universal mass for the scalar fields, generally smaller thanm _3/2, is generated. An intermediate scale can be obtained through the radiative breaking of part of the gauge group. As a consequence, the additional particles present in the spectrum get a heavy mass, and effective interactions are induced, which make possible the breaking of the electroweak group and the radiative generation of gaugino masses.     

Effects of component ratio and easy axes distribution on the exchange bias in ferromagnetic-antiferromagnetic random alloys

For a ferromagnetic (FM)-antiferromagnetic (AFM) system with composition x(FM)+(AFM)_1−x, a modified Monte Carlo Metropolis method is performed to study the effects of x and easy axes distribution at the FM/AFM nearest neighbors on exchange bias field H_E, coercivity H_C, and vertical magnetization shift M_E after cooling under different magnetic fields h_CF. When the orientations of easy axes are uniform, the x dependence of H_E and M_E undergo a non-monotonous to monotonous process with the increase of h_CF, whereas H_C shows a more complex behavior. On the other hand, for the case of the random orientation, H_C has a peak around x=0.5, while M_E decreases with the increase of x. H_E exhibits negative extrema at small x and disappears for larger x. However, abnormal positive H_E observed depends on the frustration and the distinct trends of two coercive fields with x in such a special model.     

Electric field induced avalanche breakdown and non-volatile resistive switching in the Mott Insulators AM4Q8

The Mott insulator compounds AM₄Q₈ exhibit a new type of volatile and non volatile resistive switchings that are of interest for RRAM application. We found that above a threshold electric field E _TH of the order of a few kV/cm these compounds undergo a volatile resistive switching based on an avalanche process. For electric field much higher than the threshold avalanche breakdown field, the resistive switching turns non volatile. Our EDXS and STEM analyses show that the non volatile resistive switching originating from the avalanche breakdown can neither be ascribed to local chemical modifications nor to a local phase change with symmetry breaking at a resolution better than a few nanometer. This is in strong contrast with non volatile resistive switching reported so far that are all based on chemical or structural changes. Conversely, our results suggest that the avalanche breakdown induce the collapse of the Mott insulating state at the local scale and the formation of a granular conductive filament formed by compressed metallic domains and expanded “superinsulating” domains.     

On the problem of electron-emission mechanisms in the cathode spot of a vacuum arc discharge

A criterion for the F-type mechanism of electron emission in a vacuum-arc cathode spot is developed. It is shown that the implementation of F-electron emission in the cathode spot necessitates the fulfillment of three conditions: first, generation of the optimal electric field E _opt, second, implementation of atomic-ionic balance at which the E _opt field is generated and, third, retention of the cathode temperature lower than the inversion temperature of Nottingham’s effect. The calculations show that the heat of the evaporation of cathode atoms which meets these requirements does not exceed λ_a ～ 1.1–1.2 eV. Taking the possibility of F-T-emission into account, the evaporation heat can be slightly higher than λ_a ～ 1.5–1.6 eV. However, in this case, it turns out to be fairly small. Note that the number of such metals is not very large.     

On the broken time translation symmetry in macroscopic systems: Precessing states and off-diagonal long-range order

The broken symmetry state with off-diagonal long-range order (ODLRO), which is characterized by the vacuum expectation value of the operator of creation of the conserved quantum number Q, has the time-dependent order parameter. However, the breaking of the time translation symmetry is observable only if the charge Q is not strictly conserved and may decay. This dichotomy is resolved in systems with quasi-ODLRO. These systems have two well separated relaxation times: the relaxation time τ _Q of the charge Q and the energy relaxation time τ _E . If τ _Q ? τ _E , the perturbed system relaxes first to the state with the ODLRO, which persists for a long time and finally relaxes to the full equilibrium static state. In the limit τQ → ∞, but not in the strict limit case when the charge Q is conserved, the intermediate ODLRO state can be considered as the ground state of the system at fixed Q with the observable spontaneously broken time translation symmetry. Examples of systems with quasi-ODLRO are provided by superfluid phase of liquid ⁴He, Bose-Einstein condensation of magnons (phase coherent spin precession) and precessing vortices.     

Inflation Driven by q-de Sitter

We propose a generalised de Sitter scale factor for the cosmology of early and late time universe, including single scalar field is called as inflaton. This form of scale factor has a free parameter q is called as nonextensivity parameter. When q = 1, the scale factor is de Sitter. This scale factor is an intermediate form between power-law and de Sitter. We study cosmology of such families. We show that both kinds of dark components, dark energy and dark matter simultaneously are described by this family of solutions. As a motivated idea, we investigate inflation in the framework of q-de Sitter. We consider three types of scenarios for inflation. In a single inflation scenario, we observe that, inflation ended without any specific ending inflation ?_end, the spectral index and the associated running of the spectral index are n_s ? 1 ～ ?2??, α_s ≡ 0. To end the inflation: we should have \(q=\frac {3}{4}\). We deduce that the inflation ends when the evolution of the scale factor is a(t) = e_3/4(t). With this scale factor there is no need to specify ?_end. As an alternative to have inflation with ending point, We will study q-inflation model in the context of warm inflation. We propose two forms of damping term Γ. In the first case when Γ = Γ₀, we show the scale invariant spectrum, (Harrison-Zeldovich spectrum, i.e. n_s = 1) may be approximately presented by (\(q=\frac {9}{10},~~N=70\)). Also there is a range of values of R and n_s which is compatible with the BICEP2 data where \(q=\frac {9}{10}\). In case Γ = Γ₁V(?), it is observed that small values of a number of e-folds are assured for small values of q parameter. Also in this case, the scale-invariant spectrum may be represented by \((q,N) = (\frac {9}{10},70)\). For \(q=\frac {9}{10}\) a range of values of R and n_s is compatible with the BICEP2 data. Consequently, the proposal of q-de Sitter is consistent with observational data. We observe that the non-extensivity parameter q plays a significant role in inflationary scenario.     

Electroreflectance study of the dilure magnetic semiconductor alloy Hg1−xMnxTe

We report the first electroreflectance study of the dilute magnetic semiconductor Hg_1?xMn_xTe in the photon energy region of 0.7–6 eV. The composition dependence of the E₀ + Δ₀, E₁, E₁ + Δ₁, E₀, E₂, E₂ + δ optical features has been determined for 0.015 ≤ × ≤ 0.23. We find that at room temperature the semimetal-semiconductor transition (Γ₆ – Γ₈ crossing) occurs at x = 0.05 ± 0.01. Discontinuities in the composition dependence of all the observed spectral features are seen at this value of x.     

Realizations of the exceptional modular invariant A(1)1 partition functions

We show that the E₆ and E₈ modular invariant combinations of A⁽¹⁾₁ characters in the classification of Cappelli, Itzykson and Zuber can be realized as partition functions of k=1 conformally invariant WZW models on the group manifolds of Sp(4) and G₂, respectively. Together with the D₄ combination, which is known to be realized by the WZW model on SU(3), these are the only such cases where the SU(2) local symmetry extends to a larger one. The E₇ combination is briefly discussed.     

Low-frequency polarization relaxation in PMN + 2% Li2O ferroelectric ceramics in the region of diffuse phase transition

Studies of dielectric nonlinearity in lead magnoniobate ceramics doped with lithium show that at a certain value of external field amplitude E, two peaks appear on the temperature dependences of effective dielectric permittivity ?_eff′(T). They are caused by the dynamics of the polar regions in the vicinity of diffuse phase transition and by variation in their volume under the action of field E.     

Electric field breakdown in borosilicate glass and other amorphous insulators

It is proposed that the intrinsic breakdown field strenght, E_B, can be determined from P=σE²_B where P is the power absorbed from an incident pulse of X-rays and σ is the measured conductivity.     

Calculation of the spin-lattice coupling coefficients in cubic symmetry

The relationships between spin-lattice coupling coefficients G₁₁, G₄₄ in cubic symmetry and the zero-field splittings in low symmetry have been put forward and hence the simple methods of calculating these coefficients from the formulae of zero-field splittings are given. According to these, the coefficient G₄₄ can be obtained very easily from two cases, one from the derivative of zero-field splitting D in trigonal symmetry with respect to the bonding angle β and another from the derivative of splitting E in rhombic symmetry with respect to the angle θ. So, one can, in a certain degree, check whether the formulae of D in trigonal field and E in rhombic field based on different mechanisms and models are consistent and reliable by comparing the formulae of G₄₄ obtained from the two cases.     

Fermi-condensate quantum phase transition in high-T c superconductors

The effect of a quantum phase transition associated with the appearance of fermionic condensation in an electron liquid on the properties of superconductors is considered. It is shown that the electron system in both superconducting and normal states exhibits characteristic features of a quantum protectorate after the point of this Fermi-condensate quantum phase transition. The single-particle spectrum of a superconductor can be represented by two straight lines corresponding to two effective masses M _FC * and M _L *. The M _FC * mass characterizes the spectrum up to the binding energy E ₀ , which is of the order of the superconducting gap in magnitude, and determines the spectrum at higher binding energies. Both effective masses are retained in the normal state; however, E ₀ ?4 T. These results are used to explain some remarkable properties of high-T _c superconductors and are in good agreement with recent experimental data.