Related papers: Dimensionality-Changing Transition from a Non-Ferm…
Discontinuous quantum phase transitions and the associated metastability play central roles in diverse areas of physics ranging from ferromagnetism to false vacuum decay in the early universe. Using strongly-interacting ultracold atoms in…
We study an exactly-solvable model which shows a zero-temperature transition from a non-Fermi liquid to a Fermi liquid as a function of particle density. The quantum critical point separating these two states is not associated with the…
We investigate the admittance of a metallic quantum RC circuit with a spinful single-channel lead or equally with two conducting spin-polarized channels, in which Majorana fermions play a crucial role in the charge dynamics. We address how…
We study a symmetrical double quantum dot (DD) system with strong capacitive inter-dot coupling using renormalization group methods. The dots are attached to separate leads, and there can be a weak tunneling between them. In the regime…
We present an application of high-order series expansion in the coupling constants for the ground state properties of correlated lattice fermion systems. Expansions have been generated up to order $(t/J)^{14}$ for $d=1$ and $(t/J)^8$ for…
We consider the non-Fermi liquid quantum critical state of the spin-S two-impurity Kondo model, and its potential realization in a quantum dot device. Using conformal field theory (CFT) and the numerical renormalization group (NRG), we show…
We apply conformal field theory analysis to the $k$-channel SU($N$) Kondo system, and find a peculiar behavior in the cases $N > k > 1$, which we call Fermi/non-Fermi mixing: The low temperature scaling is described as the Fermi liquid,…
We examine the equilibrium properties of lattice bosons with attractive on-site interactions in the presence of a three-body hard-core constraint that stabilizes the system against collapse and gives rise to a dimer superfluid phase formed…
We study a controlled large-$N$ theory of electrons coupled to dynamical two-level systems (TLSs) via spatially-random interactions. Such a physical situation arises when electrons scatter off low-energy excitations in a metallic glass,…
We study the relaxation properties of the Kondo lattice model using the nonequilibrium dynamical mean field formalism in combination with the non-crossing approximation. The system is driven out of equilibrium either by a magnetic field…
We investigate two equivalent, capacitively coupled semiconducting quantum dots, each coupled to its own lead, in a regime where there are two electrons on the double dot. With increasing interdot coupling a rich range of behavior is…
We study a spinless level that hybridizes with a fermionic band and is also coupled via its charge to a dissipative bosonic bath. We consider the general case of a power-law hybridization function $\Gamma(\w)\propto |\w|^r$ with $r\ge 0$,…
We study the quantum phase transition from an antiferromagnetic metal to a heavy fermion metal in the Kondo lattice model. Based on the strong coupling approach we {\it first} diagonalize the Kondo coupling term. Since this strong coupling…
The beta function of the multichannel Kondo model is calculated exactly in the limit of large spin N and channel number M=gamma*N, with constant gamma. There are no corrections in any finite order of 1/N. One zero is found at a finite…
The heavy-Fermion liquid with short-range antiferromagnetic correlations is carefully considered in the two-dimensional Kondo-Heisenberg lattice model. As the ratio of the local Heisenberg superexchange $J_{H}$ to the Kondo coupling $J_{K}$…
We study the Kondo-Heisenberg model using a fermionic representation for the localized spins. The mean-field phase diagram exhibits a zero temperature quantum critical point separating a spin liquid phase where the f-conduction…
The dynamical spin susceptibility is studied in the magnetically-disordered phase of heavy-Fermion systems near the antiferromagnetic quantum phase transition. In the framework of the $S=1/2$ Kondo lattice model, we introduce a perturbative…
The traditional multichannel Kondo effect takes place when several gapless metallic electronic channels interact with a localized spin-$S$ impurity, with the number of channels $n$ exceeding the size of the impurity spin, $n>2S$, leading to…
Mesoscopic systems constitute appealing platforms to study many-body physics with light and matter degrees of freedom. The Kondo effect refers to the screening of a spin-1/2 impurity by a cloud of conduction electrons, then forming a…
Motivated by recent experiments, we study a quasi-one dimensional model of a Kondo lattice with Ferromagnetic coupling between the spins. Using bosonization and dynamical large-N techniques we establish the presence of a Fermi liquid and a…