Coupling Constant Of Interaction Research Articles

Superfluid, Supersolid, and Checkerboard Solid in Two-Component Bosons in an Optical Lattice: Study by Means of Gross–Pitaevskii Theory and Monte-Carlo Simulations

The bosonic t–J model is a strong-on-site repulsion limit of the two-component Bose–Hubbard model and is expected to be realized by experiments of cold atoms in an optical lattice. In previous papers, we studied the bosonic t–J model by both analytical methods and numerical Monte-Carlo (MC) simulations. However, in the case of finite Jz, where Jz is the z-component coupling constant of the pseudospin interaction, the phase diagram of the model was investigated by assuming the checkerboard type of boson densities. In this study, we shall continue our previous study of the bosonic t–J model using both the Gross–Pitaevskii (GP) theory and MC simulations without assuming any pattern of boson densities. These two methods complement each other and give reliable results. We show that as Jz is increased, the superfluid state evolves into a supersolid (SS), and furthermore into a genuine solid with the checkerboard symmetry. In the present study, we propose a method identifying quantum phase transitions in the GP theory. We also study finite-temperature phase transitions of the superfluidity and the diagonal solid order of the SS by MC simulations.

Hyperfine spectrum of RbBr

The molecular beam electric resonance technique has been used to conduct a high precision examination of the hyperfine spectrum of 85Rb79Br and 85Rb81Br. Coupling constants for the nuclear electric quadrupole interactions, the spin–rotation interactions, the tensor and scalar spin–spin interactions, and their dependence on vibrational and rotational state have been determined. A slightly improved value of the electric dipole moment is also obtained, and the inclusion of an electric hexadecapole interaction for the rubidium nucleus is found to somewhat improve the fit.

The finite and large-N behaviors of independent-value matrix models

We investigate the finite and large N behaviors of independent-value O(N)-invariant matrix models. These are models defined with matrix-type fields and with no gradient term in their action. They are generically nonrenormalizable but can be handled by nonperturbative techniques. We find that the functional integral of any O(N) matrix trace invariant may be expressed in terms of an O(N)-invariant measure. Based on this result, we prove that, in the limit that all interaction coupling constants go to zero, any interacting theory is continuously connected to a pseudo-free theory. This theory differs radically from the familiar free theory consisting in putting the coupling constants to zero in the initial action. The proof is given for generic, finite-size matrix models, whereas, in the limiting case N → ∞, we succeed in showing this behavior for restricted types of actions using a particular scaling of the parameters.

EXTENDED MASS RELATION FOR SEVEN FUNDAMENTAL MASSES AND NEW EVIDENCE OF LARGE NUMBERS HYPOTHESIS

A previously derived mass relation has been extended to seven equidistant fundamental masses covering an extremely large mass range from ~10-69 to ~1053 kg. Six of these masses are successfully identified as mass of the observable universe, Eddington mass limit of the most massive stars, mass of hypothetical quantum “Gravity Atom” whose gravitational potential is equal to electrostatic potential e2/S, Planck mass, Hubble mass and mass dimension constant relating masses of stable particles with coupling constants of fundamental interactions. The seventh mass, ~10-48 kg remains unidentified and could be considered as a prediction of the suggested mass relation for an unknown fundamental mass, potentially a yet unobserved light particle. First triad of these masses describes macro objects, the other three masses belong to particle physics masses and the Planck mass appears intermediate in relation to these two groups. Additionally, new evidences of dirac Large Numbers Hypothesis (LNH) have been found in the form of series of ratios relating cosmological parameters and quantum properties of space-time. A very large number on the order of 5×1060 connects mass, density, age and size of the observable universe with Planck mass, density, time and length, respectively.

Quantum Field Model of the Origin of Matter-Energy in the Expanding Universe

The model of production of ordinary and dark matter in the decay of a hypothetical anti- gravitating medium in the form of a condensate of (zero-momentum) spinless massive particles, which fills the early universe, is proposed. The decays of these massive particles into baryons, leptons, and dark matter particles are caused by some (after-GUT) interaction with the mass scale between the electroweak and grand unification. The observed dark energy is identified with a portion of a condensate which has not decayed up to the instant of measurement. We show that the mass of dark matter particle being close to 5 GeV and the mass of massive particle of a condensate approximately equal to 15 GeV can be extracted from the WMAP and other astrophysical data about the contributions of baryon, dark matter, and dark energy densities to the total matter-energy density budget in our universe. Such a mass of light WIMP dark matter agrees with the observations of CoGeNT, DAMA, and CDMS. The numerical values of the coupling constant of after-GUT interaction and of the decay rate of massive particle of a condensate, as well as other parameters are obtained.

The Francium Trapping Facility at TRIUMF

The study of weak interactions in atoms started soon after the discovery of parity nonconservation PNC [1]. Its small size remained a challenge, but the Bouchiats [2] recognized that in an appropriate interference experiment the size of the effect of atomic parity noncon servation (APNC) scales faster than Z3, with Z the atomic number. This strong scaling has made possible not only to observe PNC effects in atoms, but to measure weak interaction coupling constants, at very low energies.

Wilsonian RG Analysis of the P-wave Nucleon–Nucleon Scattering Including Pions

We perform a Wilsonian renormalization group analysis for the nucleon–nucleon scattering in the P waves in the nuclear effective field theory including pions, in a similar way to the one done for the S-waves in our previous paper. We emphasize that the one-pion exchange interaction with large momentum transfer is of the same order as the leading contact interaction, so that there is no mismatch of the power counting. It is explicitly shown by obtaining consistent sets of renormalization group equations, that the cutoff dependence generated by the loop diagrams containing pion exchanges can be compensated by the cutoff dependence of the coupling constants of the contact interactions.

ONE-LOOP RENORMALIZATION GROUP ANALYSIS OF BOSE–FERMI MIXTURES

A weakly interacting Bose–Fermi mixture model was investigated using Wisonian renormalization group (RG). This model includes one boson–boson interaction term and one boson–fermion interaction term. The scaling dimensions of the two interaction coupling constants were calculated as 2-D at tree level and the flow equations were derived at one-loop level. We find that in the flow equations the contributions from the fermion loops go to zero as the length scale approaches infinity. In three-dimensional case two fixed points are calculated. One is the Gaussian fixed point and the other one is Wilson–Fisher fixed point. We observe that the boson–fermion interaction decouples at the Wilson–Fisher fixed point. We also find that under RG transformation the boson–fermion interaction coupling constant runs to negative infinity with a small negative initial value, which indicates a boson–fermion pairing instability. Furthermore, the possibility of emergent supersymmetry in this model was discussed.

Solvability of quantum D2 model: Projection and SUSY methods

We consider a 2-body particles quantum system with D2 algebra interaction and different coupling constants. Then we solve it by projection and supersymmetric methods. This work illustrates a natural way to construct algebraic and supersymmetric generalization of the other solvable Hamiltonians. This is an interesting work both in its own right and for the insights it offers in connection with the exact solvability of these models.

Influence of vector interactions on the hadron-quark/gluon phase transition

The hadron-quark/gluon phase transition is studied in the two-phase model. As a further study of our previous work, both the isoscalar and isovector vector interactions are included in the Polyakov loop modified Nambu--Jona-Lasinio model (PNJL) for the quark phase. The relevance of the exchange (Fock) terms is stressed and suitably accounted for. The calculation shows that the isovector vector interaction delays the phase transition to higher densities and the range of the mixed phase correspondingly shrinks. Meanwhile the asymmetry parameter of quark matter in the mixed phase decreases with the strengthening of this interaction channel. This leads to some possible observation signals being weakened, although still present. We show that these can be rather general effects of a repulsion in the quark phase due to the symmetry energy. This is also confirmed by a simpler calculation with the MIT--Bag model. However, the asymmetry parameter of quark matter is slightly enhanced with the inclusion of the isoscalar vector interaction, but the phase transition will be moved to higher densities. The largest uncertainty on the phase transition lies in the undetermined coupling constants of the vector interactions. In this respect new data on the mixed phase obtained from Heavy Ion Collisions at Intermediate Energies appear very important.

High-precision half-life measurements of atomic nuclei

In a series of measurements performed at the IGISOL facility at the Accelerator Laboratory of the University of Jyvaskyla, the half-lives of 26Si, 29P, 30,31S, 42Ti and 62Ga were measured with high precision. These half-lives are important ingredients for tests of the weak-interaction standard model and allow, together with other experimental inputs and theoretical correction terms, the determination of the vector coupling constant of the weak interaction. The IGISOL method used in Jyvakyla is an ideal tool for these measurements as it allows to access all elements without distinction of their chemical properties.

EVENT SHAPES FOR HADRONIC FINAL STATE: EXPERIMENTAL REVIEW

The analysis is presented for the first moments of collective observable distributions in two-jet events for various interaction types and for wide initial energy range. These observables include sphericity, thrust, components of transverse particle momentum, alignment and planarity. Database of experimental results created in the framework of the paper includes data for all interactions. Energy dependencies of average values for collective observables except components of transverse momentum show universal behavior for various interactions. Particle transverse momentum as well as its components increase faster for e+e- interaction with growth of [Formula: see text], than that for other interactions. Empirical analytical functions are suggested for description of energy dependence for all collective observables under study with exception of infrared-stable thrust variable. Energy dependence for average thrust is compared with QCD predictions including perturbative part and analytical phenomenological corrections which account for nonperturbative effects. Dispersive model and single dressed gluon approximation are considered for description of energy dependence of first moment of thrust distribution and estimation of strong coupling constant for various interactions as well as for joint sample. The dispersive model allow to describe average thrust versus initial energy in wide range of [Formula: see text] down to strongly nonperturbative domain [Formula: see text] at qualitative level at least. Study of event shape observables allows to obtain estimations of αS(MZ) which are in reasonable agreement both with world average value and with results extracted in the framework of other methods. Using suggested analytical fitted functions some estimations of values of collective parameters under study have been obtained for present and future facilities. In TeV energy domain average values of collective observables either depend on [Formula: see text] weakly or do not depend on initial energy at all within errors. Thus, the TeV scale can be considered as an estimation of the low boundary of asymptotic region for traditional collective parameters. Usually, multiplicity dependence of collective observables under consideration agree with power function in energy domain [Formula: see text] at qualitative level at least. Behavior of sphericity versus multiplicity and comparison of experimental results with model calculations allow to suggest that the universal estimation of the low energy boundary for experimental appearance of event jet structure in multiparticle production processes is [Formula: see text].

Testing little Higgs mechanism at future colliders

In the framework of the little higgs scenario, coupling constants of several interactions are related to each other to guarantee the stability of the higgs boson mass at one-loop level. This relation is called the little higgs mechanism. We discuss how accurately the relation can be tested at future e+e- colliders, with especially focusing on the top sector of the scenario using a method of effective lagrangian. In order to test the mechanism at the top sector, it is important to measure the Yukawa coupling of the top partner. We consider higgs associated production and threshold production of the top partner, and find that the mechanism can be tested precisely using the associate production when the center of mass energy is large enough. The threshold production also allows us to test it even if the center mass energy is not so large.

Quasi-one-dimensional scattering in a discrete model

We study quasi-one-dimensional scattering of one and two particles with short-range interactions on a discrete lattice model in two dimensions. One of the directions is tightly confined by an arbitrary trapping potential. We obtain the collisional properties of these systems both at finite and zero Bloch quasimomenta, considering as well finite sizes and transversal traps that support a continuum of states. This is made straightforward by using the exact ansatz for the quasi-one-dimensional states from the beginning. In the more interesting case of genuine two-particle scattering, we find that more than one confinement-induced resonances appear due to the nonseparability of the center-of-mass and relative coordinates on the lattice. This is done by solving its corresponding Lippmann-Schwinger-like equation. We characterize the effective one-dimensional interaction and compare it with a model that includes only the effect of the dominant, broadest resonance, which amounts to a single-pole approximation for the interaction coupling constant.

QUANTUM GRAVITY IN PLEBANSKI FORMULATION

We present a theory of four-dimensional quantum gravity with massive gravitons which may be essentially renormalizable. In Plebanski formulation of general relativity in which the tetrads, the connection and the curvature are all independent variables (and the usual relations among these quantities are valid only on-shell), we consider the nonperturbative theory of gravity with a nonzero background connection. We predict a tiny value of the graviton mass: mg≈1.5×10-42 GeV and extremely small dimensionless coupling constant of the perturbative gravitational interaction: g~10-60. We put forward the idea by Isimori56 on renormalizability of quantum gravity having multi-gravitons with masses m0, m1, …, mN-1.

Search for a permanent electric-dipole moment using atomic indium

We propose indium (In) as a possible candidate for observing the permanent electric dipole moment (EDM) arising from the violations of parity (P) and time-reversal (T) symmetries. This atom has been laser cooled and therefore the measurement of its EDM has the potential of improving on the current best EDM limit for a paramagnetic atom which comes from thallium. We report the results of our calculations of the EDM enhancement factor due to the electron EDM and the ratio of the atomic EDM to the electron-nucleus scalar-pseudoscalar (S-PS) interaction coupling constant in In in the framework of the relativistic coupled cluster theory. It might be possible to get new limits for the electron EDM and the S-PS CP violating coupling constant by combining the results of our calculations with the measured value of the EDM of In when it is available. These limits could have important implications for the standard model (SM) of particle physics.

High-resolution spectroscopy of the C–N stretching band of methylamine

The C-N stretching infrared fundamental of CH(3)NH(2) has been investigated by high-resolution laser sideband and Fourier transform synchrotron spectroscopy to explore the energy level structure and to look for possible interactions with high-lying torsional levels of the ground state and other vibrational modes. The spectrum is complicated by two coupled large-amplitude motions in the molecule, the CH(3) torsion and the NH(2) inversion, which lead to rich spectral structure with a wide range of energy level splittings and relative line intensities. Numerous sub-bands have been assigned for K values ranging up to 12 for the stronger a inversion species for the v(t) = 0 torsional state, along with many of the weaker sub-bands of the s species. The C-N stretching sub-state origins have been determined by fitting the upper-state term values to J(J + 1) power-series expansions. For comparison with the ground-state behaviour, both ground and C-N stretch origins have been fitted to a phenomenological Fourier series model that produces an interesting pattern with the differing periodicities of the torsional and inversion energies. The amplitude of the torsional energy oscillation increases substantially for the C-N stretch, while the amplitude of the inversion energy oscillation is relatively unchanged. Independent inertial scale factors ρ were fitted for the torsion and the inversion and differ significantly in the upper state. The C-N stretching vibrational energy is determined to be 1044.817 cm(-1), while the effective upper state B-value is 0.7318 cm(-1). Several anharmonic resonances with v(t) = 4 ground-state levels have been observed and partially characterized. A variety of J-localized level-crossing resonances have also been seen, five of which display forbidden transitions arising from intensity borrowing that allow determination of the interaction coupling constants.

Ultrasonic Investigation on a Cage Structure Compound PrTi2Al20

We present experimental results of elastic constants as a function of temperature ( T ) and magnetic field ( H ) for a single crystal of PrTi 2 Al 20 for the first time. A clear elastic softening was observed in the temperature dependence of elastic constants, C L =( C 11 +2 C 12 +4 C 44 )/3 and C T =( C 11 - C 12 + C 44 )/3, being suggestive of a remarkable fluctuation of quadrupolar moments O 20 and O 22 with Γ 3 symmetry. The elastic anomaly associated with a phase transition at 2.0 K exhibits the ferroquadrupolar (FQ) phase behavior under magnetic fields in accordance with the other physical properties such as magnetic susceptibility and specific heat. The softening can be explained well based on the crystalline electric field (CEF) effect model with a Γ 3 ground state. Furthermore, it was found that a coupling constant of the inter-site interaction between relevant quadrupolar moments is positive, indicating the FQ interaction mediated in this system. We argue the FQ scenario and 4 f multiplets of Pr...

Hyperfine spectrum of RbI

The molecular beam electric resonance technique has been used to conduct a high precision examination of the hyperfine spectrum of RbI. Coupling constants for the nuclear electric quadrupole interactions, the spin-rotation interactions, the tensor and scalar spin-spin interactions, and their dependence on vibrational and rotational state have been determined.

Hyperfine spectrum of NaF

The molecular beam electric resonance technique has been used to conduct a high precision examination of the hyperfine spectrum of 23Na 19F. Coupling constants for the nuclear electric quadrupole interactions, the spin–rotation interactions, the tensor and scalar spin–spin interactions, and their dependence on vibrational and rotational state have been determined.