Related papers: Fluctuation Effects on the Quadrupolar Ordering in…
The effect of the external field on the weakly-discontinuous first-order phase transition is analyzed in the frame of the Landau theory. The transformation of the free energy expansion as a power series in the order parameter is suggested…
A systematic treatment of the magnetic fluctuations effect on the properties of the normal-to-superconducting phase transition in a zero external magnetic field is given within the self-consistent approximation and the quasi-macroscopic…
By combining experimental measurements of the quasiparticle and dynamical magnetic properties of optimally electron-doped Pr$_{0.88}$LaCe$_{0.12}$CuO$_4$ with theoretical calculations we demonstrate that the conventional fermiology approach…
We study the effect of strong magnetic field on competing chiral and diquark order parameters in a regime of moderately dense quark matter. The inter-dependence of the chiral and diquark condensates through nonperturbative quark mass and…
Magnetic and multipolar ordering in f electron systems takes place at low temperatures of order 1--10 Kelvin. Combinations of first-principles with many-body calculations for such low-energy properties of correlated materials are…
Magnetic-field-induced ordering of electrons around vortices is a striking phenomenon recently found in high-$T_c$ cuprates. To identify its consequence in the quasiparticle dynamics, the magnetic-field ($H$) dependence of the…
The effect of a Zeeman magnetic field coupled to the spin of the electrons on the conducting properties of the disordered Hubbard model is studied. Using the Determinant Quantum Monte Carlo method, the temperature- and magnetic-field-…
Magnons are the low-energy excitations of magnetically ordered materials. While the magnetic moment of a ferromagnet aligns with an applied magnetic field, it has been experimentally shown that the magnetic order can be inverted by…
The thermodynamic uncertainty relation provides a universal lower bound on the product of entropy production and the fluctuations of any current. While proven for Markov dynamics on a discrete set of states and for overdamped Langevin…
We investigate the highly frustrated spin and orbital superexchange interactions in cubic vanadates. The fluctuations of $t_{2g}$ orbitals trigger a {\it novel mechanism of ferromagnetic interactions} between spins S=1 of V$^{3+}$ ions…
In the present work we analyze the influence of the charge-ordering on the magnetocaloric effect of Pr$_{1-x}$Ca$_x$MnO$_3$ manganites. The results for the samples with $x<$0.30 present the usual ferromagnetic behavior, peaking at the Curie…
The effect of fluctuations on the nuclear magnetic resonance (NMR) relaxation rate, $W$, is studied in a complete phase diagram of a 2D superconductor above the upper critical field line $H_{c2}(T)$ . In the region of relatively high…
We discuss the role of quantum fluctuations in Heisenberg antiferromagnets on face-centered cubic lattice with small dipolar interaction in which the next-nearest-neighbor exchange coupling dominates over the nearest-neighbor one. It is…
We study dilution effects in a Mott insulating state with quantum orbital degree of freedom, termed the two-dimensional orbital compass model. This is a quantum and two-dimensional version of the orbital model where the interactions along…
Understanding the pseudo-gap phase from which a superconducting state emerges is a central problem in the physics of cuprates. The phase exists below a temperature T* for less than optimal doping of holes, and no clear jump in the specific…
We study the ground state ordering of quadrupolar ordered $S=1$ magnets as a function of spin dilution probability $p$ on the triangular lattice. In sharp contrast to the ordering of $S=1/2$ dipolar N\'eel magnets on percolating clusters,…
The influence of quenched disorder on the competition between ordered states separated by a first-order transition is investigated. A phase diagram with features resembling quantum-critical behavior is observed, even using classical models.…
Characteristics of magnetic transitions in NpTGa$_5$ with T=Co, Ni, Rh are explained in a unified way with use of a crystalline electric field (CEF) model of localized 5$f^4$ electrons. The model takes a CEF doublet and a singlet as local…
The concept of the order parameter is extremely useful in physics. Here, I discuss extensions of this concept to cases when the order parameter is no longer a constant but fluctuates or oscillates in space and time. This allows one to…
We present a model to study effects from an external magnetic field, chemical potential, and finite size, on the phase structure of a massive four- and six-fermion interacting system. These effects are introduced by a method of…