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We show that the defect density $n$, for a slow non-linear power-law quench with a rate $tau^{-1}$ and an exponent $alpha>0$, which takes the system through a critical point characterized by correlation length and dynamical critical exponents $ u$ and $z$, scales as $n sim tau^{-alpha u d/ (alpha z u+1)}$ [$n sim (alpha g^{(alpha-1)/alpha}/tau)^{ u d/(z u+1)}$], if the quench takes the system across the critical point at time $t=0$ [$t=t_0 e 0$], where $g$ is a non-universal constant and $d$ is the system dimension. These scaling laws constitute the first theoretical results for defect production in non-linear quenches across quantum critical points and reproduce their well-known counterpart for linear quench ($alpha=1$) as a special case. We supplement our results with numerical studies of well-known models and suggest experiments to test our theory.
We study defect production in a quantum system subjected to a nonlinear power law quench which takes it either through a quantum critical or multicritical point or along a quantum critical line. We elaborate on our earlier work [D. Sen, K. Sengupta,
We compute the transition temperature $T_c$ and the Ginzburg temperature $T_{rm G}$ above $T_c$ near a quantum critical point at the boundary of an ordered phase with a broken discrete symmetry in a two-dimensional metallic electron system. Our calcu
At the familiar liquid-gas phase transition in water, the density jumps discontinuously at atmospheric pressure, but the line of these first-order transitions defined by increasing pressures terminates at the critical point, a concept ubiquitous in s
A quantum critical point (QCP) of the heavy fermion Ce(Ru_{1-x}Rh_x)_2Si_2 (x = 0, 0.03) has been studied by single-crystalline neutron scattering. By accurately measuring the dynamical susceptibility at the antiferromagnetic wave vector k_3 = 0.35 c
We show that a closed quantum system driven through a quantum critical point with two rates $omega_1$ (which controls its proximity to the quantum critical point) and $omega_2$ (which controls the dispersion of the low-energy quasiparticles at the cr