相关论文: Quantum order from string-net condensations and or…

Non-symmorphic symmetries protect Dirac line nodes in square net materials. This phenomenon has been most prominently observed in ZrSiS. Here, we systematically study the symmetry-protected nodal fermions that result from different ways of…

It is shown that it is possible for bound fermions on a cosmic string to form a superconducting state. Due to the attractive force between them, particles moving in opposite directions along the string form bound pairs. This involves a…

Quantum link models extend lattice gauge theories beyond the traditional Wilson formulation and present promising candidates for both digital and analog quantum simulations. Fermionic matter coupled to $U(1)$ quantum link gauge fields has…

We re-examine physical state representations in the covariant quantization of bosonic string. We especially consider one parameter family of gauge fixing conditions for the residual gauge symmetry due to null states (or BRST exact states),…

The gauge symmetry of the Standard Model is SU(3)_c x SU(2)_L x U(1)_Y for unknown reasons. One aspect that can be addressed is the low dimensionality of all its subgroups. Why not much larger groups like SU(7), or for that matter, SP(38)…

We present several models where the QCD axion arises accidentally. Confining gauge theories can generate axion candidates whose properties are uniquely determined by the quantum numbers of the new fermions under the Standard Model. The…

The standard wisdom on the origin of massless bosons in the spectrum of a Quantum Field Theory $(QFT)$ describing the interaction of gauge fields coupled to matter fields is based on two well known features: gauge symmetry, and spontaneous…

We develop a large-N expansion for Gutzwiller projected spin states. We consider valence bonds singlets, constructed by Schwinger bosons or fermions, which are variational ground states for quantum antiferromagnets. This expansion is…

We study the emergence of bosonic pairs in a system of two coupled one-dimensional fermionic chains subject to a gauge flux (two-leg flux ladder), with both attractive and repulsive interaction. In the presence of strong attractive…

Various string models of mesons and baryons include a string carrying 2 or 3 massive points (quarks or antiquarks). Rotational states (planar uniform rotations) of these systems generate quasilinear Regge trajectories and may be used for…

We study gauge theories where quasi-hidden sectors are added to the MSSM for the sake of string consistency conditions which would otherwise not be satisfied. We focus on quiver gauge theories motivated by weakly coupled type II orientifold…

We discuss a confining model for quark-antiquark system with a new color $SU_3$ gauge symmetry. New gauge transformations involve non-integrable phase factors and lead to the fourth-order gauge field equations and a linear potential. The…

Tensor networks, and in particular Projected Entangled Pair States (PEPS), are a powerful tool for the study of quantum many body physics, thanks to both their built-in ability of classifying and studying symmetries, and the efficient…

Spin-selective insulators emerge in systems composed of fermions with two internal degrees of freedom and another carrier, which could be fermionic or bosonic. These insulators are characterized by a gapless state for one kind of fermion…

Four-dimensional string theories predict in general the existence of light exotic particles with fractional electric charges. Such particles could escape present observations if they are confined by a gauge group of the "hidden" sector into…

We reconsider the question of mass generation for fermions coupled to a set of gauge bosons when the latter get their masses through the Goldstone bosons originating in a simple (i.e. not extended) technicolor sector. The fermion global…

The reasons behind the gauge symmetry of the Standard Model, U(1)xSU(2)xSU(3), are still unsettled. One obvious feature is the low dimensionality of all its subgroups. Under certain conditions, a negative answer to the question "why not…

We consider a system of composite bosons given by strongly bound fermion pairs tunneling through sites that form a low-dimensional network. It has been shown that the ground state of this system can have condensate-like properties in the…

The study of non-supersymmetric string theories is shedding light on an important corner of the string landscape and might ultimately explain why, so far, we did not observe supersymmetry in our universe. We review how misaligned…

In this thesis we deal with the specific collective phenomena in condensed matter - striped-structures formation. Such structures are observed in different branches of condensed matter physics, like surface physics or physics of…