1,721,104 research outputs found
Persistent oscillations after quantum quenches: the inhomogeneous case
Full text linkWe previously showed that a quantum quench in a one-dimensional translation invariant system produces undamped oscillations of a local observable when the post-quench state includes a single-quasiparticle mode and the observable couples to that mode [J. Phys. A 47 (2014) 402001]. Here we consider quenches that break initial translation invariance. Focusing on quenches performed only on an interval of the whole system, we analytically determine the time evolution of local observables, which occurs inside a truncated light cone spreading away from the quenched interval as time increases. If the quench excites a single-quasiparticle mode, oscillations with the frequency of the quasiparticle mass stay undamped until a time increasing with the length of the quenched interval, before eventually decaying as t−1/2. The translation invariant case with no damping is recovered as the length of the interval goes to infinity
Erratum to: Particles, conformal invariance and criticality in pure and disordered systems
Full text linkA Correction to this paper has been published: https://doi.org/10.1140/epjb/s10051-021-00076-
Angular distribution of inelastic diffraction
No full textWe examine the available data on σel and σtot for proton-proton and proton-antiproton interactions to see whether they are compatible with the picture of an expanding gray disk suggested by the supercritical pomeron solution. We conclude that the present data are compatible with values of the transparency T ⩽ 0.2
The spin-spin correlation function in the two-dimensional Ising model in a magnetic field at T=T_c
No full textThe form factor bootstrap approach is used to compute the exact contributions in the large distance expansion of the correlation function of the two-dimensional Ising model in a magnetic field at . The matrix elements of the magnetization operator present a rich analytic structure induced by the (multi) scattering processes of the eight massive particles of the model. The spectral representation series has a fast rate of convergence and perfectly agrees with the numerical determination of the correlation function
Two point correlation function in integrable QFT with anticrossing symmetry
No full textThe two-point correlation function of the stress-energy tensor for the massive deformation of the non-unitary model is computed. We compare the ultraviolet CFT perturbative expansion of this correlation function with its spectral representation given by a summation over matrix elements of the intermediate asymptotic massive particles. The fast rate of convergence of both approaches provides an explicit example of an accurate interpolation between the infrared and ultraviolet behaviours of a Quantum Field Theory
Persistent oscillations after quantum quenches in d dimensions
Full text linkWe obtain analytical results for the time evolution of local observables in systems undergoing quantum quenches in d spatial dimensions. For homogeneous systems we show that oscillations undamped in time occur when the state produced by the quench includes single-quasiparticle modes and the observable couples to those modes. In particular, a quench of the transverse field within the ferromagnetic phase of the Ising model produces undamped oscillations of the order parameter when d>1. For the more general case in which the quench is performed only in a subregion of the whole d-dimensional space occupied by the system, the time evolution occurs inside a light cone spreading away from the boundary of the quenched region as time increases. The additional condition for undamped oscillations is that the volume of the quenched region is extensive in all dimensions
Correlation functions in the two-dimensional Ising model in a magnetic field at T=T-c
No full textThe one and two-particle form factors of the energy operator in the two-dimensional Ising model in a magnetic field at are exactly computed within the form factor bootstrap approach. Together with the matrix elements of the magnetisation operator already computed in Nucl.Phys.B455:724-758,1995, they are used to write down the large distance expansion for the correlators of the two relevant fields of the model
Critical points of coupled vector-Ising systems. Exact results
Full text linkWe show that scale-invariant scattering theory allows to exactly determine the critical points of two-dimensional systems with coupled O(N) and Ising order parameters. The results are obtained for N continuous and include criticality of the loop gas type. In particular, for N = 1 we exhibit three critical lines intersecting at the Berezinskii Kosterlitz Thouless transition point of the Gaussian model and related to the Z4 symmetry of the isotropic Ashkin Teller model. For N = 2 we classify the critical points that can arise in the XY-Ising model and provide exact answers about the critical exponents of the fully frustrated XY model
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A letter from Solomon P. Ortiz to Dr. Hector P. Garcia, thanking him for a recent letter on behalf of Reverend Delfino G. Moreno over employment abroad.
No full textA letter from Solomon P. Ortiz, United States Representative from Texas, to Dr. Hector P. Garcia, thanking him for a recent letter on behalf of Reverend Delfino G. Moreno over employment abroad
The field theory of the q -> 4(+) Potts model
No full textThe q-state Potts model in two dimensions exhibits a first-order transition for q > 4. As q → 4+ the correlation length at this transition diverges. We argue that this limit defines a massive integrable quantum field theory whose lowest excitations are kinks connecting 4 + 1 degenerate ground states. We construct the S-matrix of this theory and the two-particle form factors, and hence estimate a number of universal amplitude ratios. These are in very good agreement with the results of extrapolated series in q(-1/2) as well as Monte Carlo results for q = 5. (C) 2000 Elsevier Science B.V
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