Complex networks are used to describe interactions in many real world systems, including economic, biological and social systems. An analysis was done of inter-student friendship, enmity and kinship relationships at three elementary schools by building social networks of these relationships and studying their properties. Friendship network measurements were similar between schools and produced ...

We study thermal corrections to the dispersion relations of massive fundamental particles immersed in weakly coupled non-Abelian plasmas. The cases covered include quarks in the QCD (quark-gluon) plasma, as well as N = 2 quarks and scalars in an N = 4 Super Yang-Mills plasma. We perform the calculations to leading order in a weak coupling expansion, and consider all mass scales of the fundament...

We give a simple construction yielding homology classes in (non-simply-connected) symplectic four-manifolds which admit infinitely many pairwise non-isotopic symplectic representatives. Examples are constructed in which the symplectic curves can have arbitrarily large genus. The examples are built from surface bundles over surfaces and involve only elementary techniques. As a corollary we see t...

A triplon refers to a fictitious particle that carries angular momentum $S = 1$ corresponding the elementary excitation in broad class of quantum dimerized spin systems. Such systems without magnetic order have long been studied as testing ground for properties spins. Although triplons found play central role thermal and magnets with singlet correlation, flow carried by triplons, current, has n...

We consider elementary particles in a quantum theory based on a Galois field. In this approach infinities cannot exist, the cosmological constant problem does not arise and one irreducible representation of the symmetry algebra necessarily describes a particle and its antiparticle simultaneously. In other words, the very existence of antiparticles is a strong indication that nature is described...

It is shown that a sufficiently strong four-spin interaction in the spin-1/2 spin ladder can cause dimerization. Such interaction can be generated either by phonons or (in the doped state) by the conventional Coulomb repulsion between the holes. The dimerized phases are thermodynamically undistinguishable from the Haldane phase, but have dramatically different correlation functions: the dynamic...

The excitation spectrum of the one-dimensional spin-orbital model in a magnetic field is studied, using a recently developed dynamical density matrix renormalization group technique. The method is employed on chains with up to 80 sites, and examined for test cases such as the spin-1/2 antiferromagnetic Heisenberg chain, where the excitation spectrum is known exactly from the Bethe Ansatz. In th...

We study nonhomogeneous quantum quenches in a one-dimensional gas of repulsive spin-$1/2$ fermions, as described by the integrable Yang-Gaudin model. By means generalized hydrodynamics (GHD), we analyze detail real-time evolution following sudden change confining potential. consider particular release protocols and trap quenches, including version Newton's cradle. At zero temperature, employ si...

A detailed exact-diagonalization study is made for the doping dependence of the single-particle spectral function A(k, ω) and momentum distribution function n(k) of the two-dimensional t−J model as a representative model for doped Mott insulators. The results for A(k, ω) show unambiguously that the rigid-band behavior is realized in the small-cluster t−J model: upon doping, the uppermost states...

Spacetime is modelled by binary relations by the classes of the automorphisms GL( I C) of a complex 2-dimensional vector space with respect to the definite unitary subgroup U(2). In extension of Feynman propagators for particle quantum fields representing only the tangent spacetime structure, global spacetime representations are given, formulated as residues using energy-momentum distributions ...