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Variational Ansatz for the Ground State of the Quantum Sherrington-Kirkpatrick Model
Paul M Schindler1,2, Tommaso Guaita2,3,4, Tao Shi5,6
1Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden, Germany.
Physical Review Letters
|December 9, 2022
Summary
We introduce a new Ansatz to study quantum spin glasses, accurately predicting ground state energy and phase transitions. This method reveals insights into entanglement structure, challenging previous theories.
Area of Science:
- Quantum physics
- Condensed matter theory
- Statistical mechanics
Background:
- The quantum Sherrington-Kirkpatrick (SK) model is a key model for understanding quantum spin glasses.
- Accurately characterizing ground states and phase transitions in such models is crucial but challenging.
Purpose of the Study:
- To develop a novel Ansatz for the ground states of the quantum SK model.
- To investigate previously unexplored aspects, including the nonvanishing longitudinal field regime and ground state entanglement.
Main Methods:
- Utilizing an Ansatz based on generalized coherent states.
- Analyzing the entanglement structure using an ensemble of weighted graph states.
Main Results:
- The Ansatz successfully captures fundamental properties like ground state energy and the spin glass phase transition.
- Ground state entanglement exhibits a volume law, contradicting predictions from entanglement monogamy.
Conclusions:
- The generalized coherent states Ansatz provides a powerful tool for studying quantum spin glasses.
- The observed volume law entanglement offers new perspectives on quantum correlations in these systems.
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