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Observing the emergence of a quantum phase transition shell by shell
Luca Bayha1, Marvin Holten2, Ralf Klemt3
1Physikalisches Institut der Universität Heidelberg, Heidelberg, Germany. bayha@physi.uni-heidelberg.de.
Nature
|November 26, 2020
Summary
Researchers observed the early stages of a quantum phase transition in ultracold atoms. This study reveals the precursor to a Higgs mode, offering insights into how collective behavior emerges in many-body systems.
Area of Science:
- Atomic physics
- Condensed matter physics
- Quantum many-body physics
Background:
- Many-body physics explains phenomena like broken symmetry and phase transitions.
- Understanding the emergence of collective behavior from individual particles is a long-standing goal.
Purpose of the Study:
- To observe the few-body precursor of a quantum phase transition.
- To identify the Higgs mode precursor in a controlled mesoscopic system.
Main Methods:
- Utilizing ultracold fermions in two-dimensional harmonic potentials.
- Preparing closed-shell configurations (2, 6, 12 atoms) with high fidelity.
- Performing spectroscopy while tuning pair energy and analyzing atom counting statistics.
Main Results:
- Observed the lowest resonance consisting of coherently excited pairs.
- Identified a distinct non-monotonic interaction dependence for this many-body excitation.
- Confirmed the excitation as the Higgs mode precursor through numerical calculations.
Conclusions:
- Demonstrated an atomic simulator for studying collective phenomena and the thermodynamic limit.
- Provided experimental evidence for the few-body precursor of a quantum phase transition.
- Linked mesoscopic observations to fundamental many-body physics concepts.
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