Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 64: BKT Physics
TT 64.1: Talk
Wednesday, March 11, 2026, 16:45–17:00, HSZ/0103
Berezinskii-Kosterlitz-Thouless renormalization group flow at a quantum phase transition — •Matthias Thamm1, Harini Radhakrishnan2, Hatem Barghathi2, Chris Herdman3, Arpan Biswas2, Bernd Rosenow1, and Adrian Del Maestro2 — 1Leipzig University — 2University of Tennessee, Knoxville — 3Middlebury College, Vermont
We present a controlled numerical study of the Berezinskii-Kosterlitz-Thouless (BKT) transition in the one-dimensional Bose-Hubbard model at unit filling, providing evidence of the characteristic logarithmic finite-size scaling of the BKT transition. Employing density matrix renormalization group and quantum Monte Carlo simulations under periodic boundary conditions, together with a systematic finite-size scaling analysis of bipartite particle number fluctuations, we resolve boundary-induced complications that previously obscured critical scaling. We demonstrate that a suitably chosen central region under open boundaries reproduces universal renormalization group signatures, reconciling earlier discrepancies. Finally, leveraging a nonparametric Bayesian analysis, we determine the critical interaction strength with high precision, establishing a benchmark for BKT physics in one-dimensional quantum models.
Keywords: BKT transition; renormalization group flow; quantum phase transition; Bose-Hubbard model; DMRG