| Title | Non-analytic behaviour of order parameter correlation lengths in the quantum Ising spin chain |
|---|---|
| Speaker | Marton Kormos (Budapest University of Technology and Economics) |
| Date&time |
📅 Tuesday, December 16 🕓 11.00 (Rome) |
| Location | Room 138 (Via Bonomea 265, First Floor) |
| Abstract | I will report recent results on the finite temperature dynamical correlation functions of the magnetization operator in the quantum Ising spin chain. First I will present our findings in the Ising quantum field theory describing the scaling limit of the spin chain. Starting from a finite temperature form factor series and a Fredholm determinant representation of the correlators, we explored all space-time and temperature regimes in both the ordered and disordered phases. Apart from confirming existing analytic predictions for the asymptotic behavior of the correlations, we derived a new closed form expression for the correlation length for space-like separations that has some unusual properties: it is a non-analytic function of both the space-time direction and the temperature, and its temperature dependence is non-monotonic. I will then turn to the spin chain, where using methods based on hydrodynamic fluctuations I will show that the correlation length of the order parameter shows similar non-analytic behaviour. This means that, in contrast to the common belief, collective effects induced by quantum fluctuations can persist in the dynamics even at finite temperature. |
| 🔗 Past seminars | |
| 🔗 Past journal club meetings |
