Most physical systems exhibit scale invariance only when fine-tuning to a phase transition or a scattering resonance. Remarkably, a classical gas in two dimensions is scale invariant for an arbitrary strength of contact interaction. This has striking consequences for its nonequilibrium scaling dynamics, in particular the breathing motion in a harmonic trapping potential. For a two-dimensional Fermi gas, instead, quantum fluctuations violate the classical scaling symmetry and give rise to a quantum anomaly. I will discuss the origin of this scale anomaly and how it affects the equation of state, pairing properties, quantum bounds to spin transport, and nonequilibrium scaling dynamics.

連絡教員　物理学系　西田　祐介（内線3614）