Hideo Fukutome, M. Yamamura, Seiya Nishiyama,
A new many-body theory for fermions is proposed wihich is based on the SO(2N+1) Lie algebra of the fermion operators consisted of the annihilation-creation operators and ... is introduced. A new bose representation for the fermion Lie operators is obtained by mapping the fermion Lie operators into the regular representation of the ... annihilation-creation operators and the pair operators of fermions are represented by the closed first order differential ... SO(2N+1) group. An exact representation of fermion wavefunctions in a form similar to the wavefunction ...
Tópico(s): Advanced NMR Techniques and Applications
1977 - Oxford University Press | Progress of Theoretical Physics
... quantum number (baryon or lepton number) associated with fermions. There are two unusual features. Firstly, there is ... supermultiplets in which the spinor particle with unit fermion number is accompanied by a scalar particle which carries two units of fermion number. Only in a very restricted class of ... appearance of such difermions be avoided. Secondly, the fermion number content of a supermultiplet is governed by ... shown that, in scalar supermultiplets, right-handed spinor fermions are associated with ordinary scalar bosons while left- ...
Tópico(s): Black Holes and Theoretical Physics
1975 - Elsevier BV | Nuclear Physics B
Springer Link
F. del Águila, Mark J. Bowick,
In the Glashow-Weinberg-Salam model the fermions have ΔI = 12 masses from the breaking of the weak SU(2) gauge symmetry. In many enlarged models, such as those from grand unified and/or supersymmetric theories, there are additional fermions with undetermined ΔI = 0 (SU(2) invariant) masses. We study these new fermions. They induce flavour changing neutral currents. We show that the mixing angles of ΔI = 0 fermions of mass order M with normal ΔI = 12 fermions of mass order m ⪡ M are order η ... model-dependent mixing parameter of order a normal fermion mass, the amplitudes of all FCNC processes are ...
Tópico(s): High-Energy Particle Collisions Research
1983 - Elsevier BV | Nuclear Physics B
Springer Link
... energy dispersions, and velocities of the charge c fermions and spin-neutral two-spinon s1 fermions of a square-lattice quantum liquid referring to ... discrete momentum values of the c and s1 fermions are good quantum numbers so that in contrast ... one-and two-electron subspace a composite s1 fermion consists of a spin-singlet spinon pair plus ... limit of infinite on-site interaction the c fermions become non-interacting spinless fermions and the s1 fermion occupancy configurations that generate the spin degrees of ...
Tópico(s): Quantum and electron transport phenomena
2009 - Elsevier BV | Nuclear Physics B
Andrzej J. Buras, Björn Duling, Stefania Gori,
We reconsider the impact of heavy vector-like fermions on the couplings of standard model (SM) quarks ... the SM Higgs boson H. Integrating out these fermions at tree level we derive general formulae that ... the case of the lightest Kaluza-Klein (KK) fermions in a Randall-Sundrum (RS) model with a ... mixing of the SM quarks with the KK fermions, which is guaranteed by the underlying P_LR symmetry. We find that the impact of KK fermions on the Z-couplings, while not negligible, is ... the tb coupling where the impact of KK fermions can in principle be larger than the effects ...
Tópico(s): Black Holes and Theoretical Physics
2009 - Springer Nature | Journal of High Energy Physics
Springer Link
David Hsieh, Yipu Xia, Dong Qian, L. Andrew Wray, J. H. Dil, Fabian Meier, Jürg Osterwalder, L. Patthey, J. G. Checkelsky, N. P. Ong, А. В. Федоров, Hsin Lin, Arun Bansil, D. Grauer, Y. S. Hor, R. J. Cava, M. Zahid Hasan,
Helical Dirac fermions-charge carriers that behave as massless relativistic particles with an intrinsic angular momentum (spin) locked to its translational ... the anomalous quantization of magneto-electric coupling, half-fermion states that are their own antiparticle, and charge ... of which are not possible with conventional Dirac fermions of the graphene variety. Helical Dirac fermions have so far remained elusive owing to the ... of necessary spin-sensitive measurements and because such fermions are forbidden to exist in conventional materials harbouring ...
Tópico(s): Quantum and electron transport phenomena
2009 - Nature Portfolio | Nature
... perform finite-temperature grand-canonical simulations of ideal fermions in arbitrary external potentials is introduced. This scheme ... evaluation of the grand-canonical function of lattice fermions. As an application, we present results on the phase behavior of a mixture of fermions and hard spheres. A simple analytic model of solvated fermions in a hard-sphere fluid is also studied. ... phase separation between a pure delocalized phase of fermions and a homogeneous solution of solvated fermions. These ...
Tópico(s): Material Dynamics and Properties
1992 - American Institute of Physics | The Journal of Chemical Physics
Alexander P. Albus, S. A. Gardiner, Fabrizio Illuminati, Martin Wilkens,
... dilute homogeneous mixture of bosons and spin-polarized fermions at zero temperature. We first construct the formal ... especially focus on the description of the boson-fermion interaction. To do so we need to introduce the renormalized boson-fermion $T$ matrix, which we determine to second order in the boson-fermion $s$-wave scattering length. We also discuss how ... term beyond mean field stems from the boson-fermion interaction and is proportional to ${a}_{\mathrm{BF}}{ ... sum of the kinetic energy of the free fermions, the boson-boson mean-field interaction, the usual ...
Tópico(s): Physics of Superconductivity and Magnetism
2002 - American Physical Society | Physical Review A
Sudhansu S. Mandal, J. K. Jain,
... effect of appropriate particles, namely electrons or composite fermions. This paper investigates theoretically the feasibility of nested states of composite fermions which would lead to a quantum Hall effect ... understood as integral quantum Hall effect of composite fermions. The weak residual interaction between composite fermions will play a crucial role in the establishment ... opening a gap in a partially filled composite-fermion level. To treat the problem of interacting composite fermions, we develop a powerful method that allows us ...
Tópico(s): Physics of Superconductivity and Magnetism
2002 - American Physical Society | Physical review. B, Condensed matter
M. Iskin, C. A. R. Sá de Melo,
... the bosons correspond to Feshbach molecules and the fermions correspond to excess atoms. First, we discuss the three and four fermion scattering processes, and use the exact boson-fermion and boson-boson scattering lengths to generate the phase diagrams in terms of the underlying fermion-fermion scattering length. In three dimensions, in addition to ... separation between pure unpaired (excess) and pure paired fermions (molecular bosons); and (ii) phase separation between pure excess fermions and a mixture of excess fermions and molecular ...
Tópico(s): Physics of Superconductivity and Magnetism
2008 - American Physical Society | Physical Review A
... theory of torsion-free gravity coupling to massless fermions, the four-fermion interaction is induced and its strength is a ... parameter. We study the dynamics of the four-fermion interaction to determine whether effective bilinear terms of massive fermion fields are generated. Calculating one-particle-irreducible two-point functions of fermion fields, we identify three different phases and two ... phase transitions characterized by the strength of four-fermion interaction: (1) chiral symmetric phase for massive fermions ...
Tópico(s): Cosmology and Gravitation Theories
2008 - Elsevier BV | Physics Letters B
Monique Combescot, O. Betbeder-Matibet, François Dubin,
... theories for quantum particles were restricted to elementary fermions or elementary bosons, the treatment of interactions between ... us to treat composite bosons made of two fermions as an entity, while dealing with their underlying fermionic components exactly. Pauli exclusion principle between fermions of two composite bosons appears through a set of dimensionless "Pauli scatterings" which correspond to fermion exchanges between composite bosons, in the absence of fermion interaction. In addition to these Pauli scatterings, composite ...
Tópico(s): Physics of Superconductivity and Magnetism
2008 - Elsevier BV | Physics Reports
We propose a new approach to the fermion sign problem in systems where there is a coupling $U$ such that when it is infinite the fermions are paired into bosons, and there is no fermion permutation sign to worry about. We argue that as $U$ becomes finite, fermions are liberated but are naturally confined to regions which we refer to as fermion bags. The fermion sign problem is then confined to these bags ... determinantal trick. In the parameter regime where the fermion bags are small and their typical size does ...
Tópico(s): Physics of Superconductivity and Magnetism
2010 - American Physical Society | Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology
Taro Kimura, Tatsuhiro Misumi,
... we generalize to higher dimensions several types of fermion actions on the hyperdiamond lattice including a two-parameter class of minimal-doubling fermions "Creutz fermion" and a simple fermion with sufficient discrete symmetry "BBTW fermion". Then it is shown that they possess some ... in common with the four-dimensional case: BBTW fermions in higher even dimensions inevitably yield unphysical degrees of freedom. Creutz fermions are defined on the distorted lattices, and they ... Creutz action to yield minimal-doubling and physical fermions becomes narrower with the dimension getting higher, thus ...
Tópico(s): Rare-earth and actinide compounds
2010 - Oxford University Press | Progress of Theoretical Physics
R. Sekhar Chivukula, Neil D. Christensen, Baradhwaj Coleppa, Elizabeth H. Simmons,
The scale of fermion mass generation can, as shown by Appelquist and Chanowitz, be bounded from above by relating it to the scale ... unitarity violation in the helicity nonconserving amplitude for fermion-anti-fermion pairs to scatter into pairs of longitudinally polarized ... depends on the mass of the additional vectorlike fermion states that occur in these theories (the states ... analogs of Kaluza-Klein partners of the ordinary fermions in a five-dimensional theory). For sufficiently light vector fermions, and for a deconstructed theory with sufficiently many ...
Tópico(s): Quantum Chromodynamics and Particle Interactions
2007 - American Physical Society | Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology
The Yukawa-Higgs/Ginsparg-Wilson-fermion construction of chiral lattice gauge theories described in hep-lat/0605003 uses exact lattice chirality to decouple the massless chiral fermions from a mirror sector, whose strong dynamics is ... to give cutoff-scale mass to the mirror fermions without breaking the chiral gauge symmetry. In this ... to an XY model coupled to Ginsparg-Wilson fermions. For the mirror fermions to acquire cutoff-scale mass it is believed ... use analytic and Monte-Carlo methods with dynamical fermions to study the scalar and fermion susceptibilities, and ...
Tópico(s): Theoretical and Computational Physics
2007 - Springer Nature | Journal of High Energy Physics
Produção Nacional
Revisado por pares
... model to study a collapse in a degenerate fermion–fermion mixture (DFFM) of different atoms. Due to a strong Pauli-blocking repulsion among identical spin-polarized fermions at short distances, there cannot be a collapse for repulsive interspecies fermion–fermion interaction. However, there can be a collapse for a sufficiently attractive interspecies fermion–fermion interaction in a DFFM of different atoms. Using ... DFFM initiated by a jump in the interspecies fermion–fermion interaction (scattering length) to a large negative ( ...
Tópico(s): Physics of Superconductivity and Magnetism
2006 - IOP Publishing | New Journal of Physics
Wolfgang Böck, Asit K. De, E. Focht, Jan Smit,
The fermion mass spectrum is studied in the quenched approximation in the strong coupling vortex phase (VXS) of a ... 1)$_L \otimes$U(1)$_R$ symmetric scalar-fermion model in two dimensions. In this phase fermion doublers can be completely removed from the physical ... a strong Wilson-Yukawa coupling. The lowest lying fermion spectrum in this phase consists most probably only of a massive Dirac fermion which has charge zero with respect to the $ ... 1)_L$ group. We give evidence that the fermion which is charged with respect to that subgroup ...
Tópico(s): Black Holes and Theoretical Physics
1993 - Elsevier BV | Nuclear Physics B
It is shown that an arbitrary fermion hopping Hamiltonian can be mapped into a system with no fermion fields, generalizing an earlier model of Levin and Wen. All operators ... obtained. The same methods apply to Majorana (half) fermions, which for Cartesian lattices mitigate the fermion doubling problem. The generality of these results suggests that the observation of Fermion excitations in nature does not demand that anticommuting Fermion fields be fundamental.
Tópico(s): Topological Materials and Phenomena
2005 - American Physical Society | Physical Review Letters
... discuss general properties of a system of heavy fermions of one kind (including antiparticles) interacting with rather light bosons of one kind. Fermion chemical potential is assumed to be small, $\mu_ ... min} (T_{\rm bl.f}, m_{b})$, the fermion mass shell proves to be partially blurred due to multiple fermion rescatterings on virtual bosons, $m_{b}$ is the ... to a complete blurring of the gap between fermion-antifermion continua, $m_f$ is the fermion mass. As the result, the ratio of the number of fermion-antifermion pairs to the number provided by the ...
Tópico(s): High-pressure geophysics and materials
2004 - Elsevier BV | Nuclear Physics A
We study the pairing state of composite fermions (CF's) at even denominator Landau level fillings. We introduce the composite fermion operators by the Rajaraman-Sondhi nonunitary transformation. The resulting Hamiltonian ... Hermitian term has the effect of destabilizing composite fermions. However, composite fermions are stabilized when the short-range Coulomb interaction ... enough. Projecting into the Hilbert space where composite fermions are stabilized, we derive the effective Hamiltonian for ... we discuss the condition for pairing of composite fermions within mean-field theory. We show that the ...
Tópico(s): Topological Materials and Phenomena
2000 - American Physical Society | Physical review. B, Condensed matter
The chiral fermion model with local multifermion interactions proposed in Nucl. Phys. B 486 (1997) 282 and Phys. Rev. D 61 ( ... Following the previous analysis of massive and massless fermion spectra in the scaling region, we compute the ... particle-irreducible coupling vertices between gauge field and fermions by the strong multifermion coupling expansion and analytical ... We show a peculiar scenario that a massless fermion is SUL(2)-chirally gauged in the low energy and 15 non-degenerate massive Dirac fermions are SUL(2)-vectorially gauged at the lattice ...
Tópico(s): High-Energy Particle Collisions Research
2000 - Elsevier BV | Nuclear Physics B
Jiunn-Wei Chen, Jin-Yi Pang, Shi Pu, Qun Wang,
... action and the kinetic equation for massive Dirac fermions in electromagnetic fields. The non-Abelian Berry phase structure emerges from two helicity states of massive fermions with positive energy. The classical spin emerges as ... 2) helicity space. The continuity equations for the fermion number and the classical spin are derived. The fermion number is conserved while the spin charge is ... coefficients of the chiral magnetic effect for the fermion and axial currents in the chiral limit can ... spin and non-Abelian Berry phase of Dirac fermions arising from the fermion mass.
Tópico(s): High-Energy Particle Collisions Research
2014 - American Physical Society | Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D, Particles, fields, gravitation, and cosmology