Defenu, N. (2019). Quantum scale anomaly and spatial coherence in a 2D Fermi superfluid. Perimeter Institute for Theoretical Physics. https://pirsa.org/19070028
MLA
Defenu, Nicolo. Quantum scale anomaly and spatial coherence in a 2D Fermi superfluid. Perimeter Institute for Theoretical Physics, Jul. 09, 2019, https://pirsa.org/19070028
BibTex
@misc{ scivideos_PIRSA:19070028,
doi = {10.48660/19070028},
url = {https://pirsa.org/19070028},
author = {Defenu, Nicolo},
keywords = {Quantum Matter},
language = {en},
title = {Quantum scale anomaly and spatial coherence in a 2D Fermi superfluid},
publisher = {Perimeter Institute for Theoretical Physics},
year = {2019},
month = {jul},
note = {PIRSA:19070028 see, \url{https://scivideos.org/index.php/pirsa/19070028}}
}
Quantum anomalies are violations of classical scaling symmetries caused by quantum fluctuations. Although they appear prominently in quantum field theory to regularize divergent physical quanti- ties, their influence on experimental observables is difficult to discern. Here, we discovered a striking manifestation of a quantum anomaly in the momentum-space dynamics of a 2D Fermi superfluid of ultracold atoms. We measured the position and pair momentum distribution of the superfluid during a breathing mode cycle for different interaction strengths across the BEC-BCS crossover. Whereas the system exhibits self-similar evolution in the weakly interacting BEC and BCS limits, we found a violation in the strongly interacting regime. The signature of scale-invariance breaking is enhanced in the first-order coherence function. In particular, the power-law exponents that char- acterize long-range phase correlations in the system are modified due to this effect, indicating that the quantum anomaly has a significant influence on the critical properties of 2D superfluids.