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Experimental observation of Lee-Yang zeros
Xinhua Peng1, Hui Zhou1, Bo-Bo Wei2
1Hefei National Laboratory for Physical Sciences at Microscale, Department of Modern Physics, and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China.
Physical Review Letters
|January 24, 2015
Summary
Scientists observed Lee-Yang zeros, critical points in complex physical parameters, for the first time. This breakthrough in quantum coherence experiments allows studying thermodynamics in the complex plane.
Area of Science:
- Quantum physics
- Statistical mechanics
- Condensed matter physics
Background:
- Lee-Yang zeros are fundamental to understanding thermodynamics in many-body systems.
- They signify points where partition functions vanish, leading to free energy divergence.
- Previously, experimental observation was impossible due to their occurrence at unphysical complex parameter values.
Purpose of the Study:
- To achieve the first experimental observation of Lee-Yang zeros.
- To demonstrate a novel method for probing thermodynamics in the complex plane.
- To reconstruct thermodynamic properties from experimentally measured Lee-Yang zeros.
Main Methods:
- Utilized quantum coherence measurements of a probe spin.
- Coupled the probe spin to an Ising-type spin bath.
- Leveraged quantum evolution to effectively introduce an imaginary magnetic field.
Main Results:
- Successfully observed Lee-Yang zeros experimentally.
- Reconstructed the free energy of the spin bath using the measured zeros.
- Determined the phase transition temperature of the spin bath.
Conclusions:
- This experiment provides the first direct observation of Lee-Yang zeros.
- It opens new avenues for exploring complex-valued thermodynamics experimentally.
- The findings validate theoretical predictions and offer a new tool for condensed matter research.
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