INDICATIONS OF A ΔI=1/2 RULE IN THE STRONG COUPLING REGIME

1988 ◽  
Vol 03 (06) ◽  
pp. 1385-1412
Author(s):  
IAN G. ANGUS
Keyword(s):  
Lattice Qcd ◽  
Strong Coupling ◽  
Computer Algebra ◽  
Free Parameter ◽  
Hamiltonian Formalism ◽  
Strong Coupling Expansion ◽  
Calculation Scheme ◽  
Strong Coupling Regime ◽  
Weak Decays ◽  
The One

We will attempt to understand the ΔI=1/2 pattern of the nonleptonic weak decays of the kaons. The calculation scheme employed is the Strong Coupling Expansion of lattice QCD. Kogut-Susskind fermions are used in the Hamiltonian formalism. We will describe in detail the methods used to expedite this calculation, all of which was done by computer algebra. The final result is very encouraging. Even though an exact interpretation is clouded by the presence of irrelevant operators, and questions of lattice artifacts, a signal of the ΔI=1/2 rule appears to be observable. With an appropriate choice of the one free parameter, enhancements greater than those observed experimentally can be obtained. We also point out a number of surprising results which we turn up in the course of the calculation.

scholarly journals Dual Formulation and Phase Diagram of Lattice QCD in the Strong Coupling Regime

2018 ◽  
Vol 175 ◽  
pp. 07047 ◽  
Author(s):  
Giuseppe Gagliardi ◽  
Jangho Kim ◽  
Wolfgang Unger
Keyword(s):  
Lattice Qcd ◽  
Strong Coupling ◽  
Strong Coupling Expansion ◽  
Strong Coupling Limit ◽  
Strong Coupling Regime ◽  
Staggered Fermions ◽  
Chiral Transition ◽  
Occupation Numbers ◽  
Sign Problem ◽  
Limiting Case

We present the computation of invariants that arise in the strong coupling expansion of lattice QCD. These invariants are needed for Monte Carlo simulations of Lattice QCD with staggered fermions in a dual, color singlet representation. This formulation is in particular useful to tame the finite density sign problem. The gauge integrals in this limiting case β → 0 are well known, but the gauge integrals needed to study the gauge corrections are more involved. We discuss a method to evaluate such integrals. The phase boundary of lattice QCD for staggered fermions in the μB – T plane has been established in the strong coupling limit. We present numerical simulations away from the strong coupling limit, taking into account the higher order gauge corrections via plaquette occupation numbers. This allows to study the nuclear and chiral transition as a function of β.

Ferromagnetism in the strong-coupling regime of the one-dimensional Kondo-lattice model

1992 ◽  
Vol 46 (21) ◽  
pp. 13838-13846 ◽  
Author(s):  
Manfred Sigrist ◽  
Hirokazu Tsunetsugu ◽  
Kazuo Ueda ◽  
T. M. Rice
Keyword(s):  
Strong Coupling ◽  
Lattice Model ◽  
Kondo Lattice ◽  
Strong Coupling Regime ◽  
One Dimensional ◽  
Kondo Lattice Model ◽  
The One

ISOSPIN–SPIN INTERCHANGE SYMMETRY AND TWO-BARYON BOUND STATES IN (3+1)-DIMENSIONAL LATTICE QCD WITH TWO-FLAVORS AND STRONG COUPLING

2011 ◽  
Vol 26 (25) ◽  
pp. 4387-4404
Author(s):  
PAULO A. FARIA DA VEIGA ◽  
MICHAEL O'CARROLL ◽  
ANTÔNIO FRANCISCO NETO
Keyword(s):  
Binding Energy ◽  
Lattice Qcd ◽  
Strong Coupling ◽  
Bound States ◽  
Spin Symmetry ◽  
Exchange Potential ◽  
Strong Coupling Regime ◽  
Spectral Structure ◽  
Lattice Action ◽  
Baryon Spectrum

We determine two-baryon bound states in a 3+1 lattice QCD model with improved Wilson action and two flavors. We work in the strong coupling regime: small hopping parameter κ > 0 and much smaller plaquette coupling β > 0. In this regime, it is known that the low-lying energy–momentum spectrum is comprised of baryons and mesons with asymptotic masses -3 ln κ and -2 ln κ, respectively. We show that the dominant baryon–baryon interaction is an order κ2 space-range-one [Formula: see text]-exchange potential. We also show that this interaction has an important and novel isospin–spin interchange symmetry relating the various possible bound states, and then governing the two-baryon spectral structure. Letting S(I) denote the total spin (total isospin) of the two-baryon bound states, S, I = 0, 1, 2, 3, we find bound states with asymptotic binding energy κ2/4, for I+S = 1, 3, and 4 (here, with I = S = 2); κ2/12, for I+S = 0, 2, 4 and 3 (here, with I = 1, 2). In particular, we show that the two-baryon spectrum contains deuteron (I = 0), diproton (I = 1) and dineutron (I = 1)-like bound states. Using the isospin–spin symmetry, we can circumvent the lack of spin symmetry of the lattice action and show they all have the same asymptotic binding energy, namely κ2/4. Our analysis uses convenient two and four-baryon correlations, their spectral representations and a lattice Bethe–Salpeter equation, which is solved in a ladder approximation. For the isospin, spin part of the interaction, we obtain a permanent representation which describes the interaction of the individual spins and isospins of the quarks of one baryon with those of the other baryon.

scholarly journals HAMILTONIAN LATTICE QCD WITH WILSON FERMIONS AT STRONG COUPLING

2001 ◽  
Vol 16 (27) ◽  
pp. 4499-4510 ◽  
Author(s):  
YI-ZHONG FANG ◽  
XIANG-QIAN LUO
Keyword(s):  
Lattice Qcd ◽  
Strong Coupling ◽  
Unitary Transformation ◽  
Vacuum Energy ◽  
Strong Coupling Expansion ◽  
Transformation Method ◽  
Chiral Condensate ◽  
Effective Hamiltonian ◽  
Hamiltonian Lattice ◽  
Wilson Fermions

Hamiltonian lattice QCD with Wilson fermions is investigated systematically by strong-coupling expansion up to the second order. The effective Hamiltonian is diagonalized by Bogoliubov transformation. The vacuum energy, chiral condensate, pseudoscalar and vector meson masses are calculated. The comparison with the unitary transformation method by Luo and Chen is also made. The method discussed in this paper has potential application to QCD at finite density.

Strong Coupling: Polariton Bose Condensation

2017 ◽  
Author(s):  
Alexey V. Kavokin ◽  
Jeremy J. Baumberg ◽  
Guillaume Malpuech ◽  
Fabrice P. Laussy
Keyword(s):  
Strong Coupling ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Dissipative System ◽  
Bose Condensation ◽  
Einstein Condensation ◽  
Strong Coupling Regime ◽  
Stimulated Scattering ◽  
Exciton Polaritons ◽  
Bose Einstein

In this Chapter we address the physics of Bose-Einstein condensation and its implications to a driven-dissipative system such as the polariton laser. We discuss the dynamics of exciton-polaritons non-resonantly pumped within a microcavity in the strong coupling regime. It is shown how the stimulated scattering of exciton-polaritons leads to formation of bosonic condensates that may be stable at elevated temperatures, including room temperature.

Strong coupling: resonant effects

2017 ◽  
Author(s):  
Alexey V. Kavokin ◽  
Jeremy J. Baumberg ◽  
Guillaume Malpuech ◽  
Fabrice P. Laussy
Keyword(s):  
Strong Coupling ◽  
Experimental Studies ◽  
Strong Coupling Regime ◽  
Theoretical Studies ◽  
Stimulated Scattering ◽  
Quantum Theories ◽  
Pump Probe ◽  
Exciton Polaritons ◽  
Linear Optical Properties ◽  
Experimental And Theoretical Studies

This chapter presents experimental studies performed on planar semiconductor microcavities in the strong-coupling regime. The first section reviews linear experiments performed in the 1990s that evidence the linear optical properties of cavity exciton-polaritons. The chapter is then focused on experimental and theoretical studies of resonantly excited microcavity emission. We mainly describe experimental configuations in which stimulated scattering was observed due to formation of a dynamical condensate of polaritons. Pump-probe and cw experiments are described in addition. Dressing of the polariton dispersion and bistability of the polariton system due to inter-condensate interactions are discussed. The semiclassical and the quantum theories of these effects are presented and their results analysed. The potential for realization of devices is also discussed.

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