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Static Magnetic Response of Non-Fermi-Liquid Density
1Stanford Institute for Theoretical Physics, Stanford University, Stanford, California 94305, USA.
Physical Review Letters
|September 27, 2017
Summary
The density response of fermion systems to magnetic fields is determined by Fermi volume and Berry curvature, even for interacting systems. This finding applies universally to Fermi liquids and non-Fermi liquids, independent of specific models.
Area of Science:
- Condensed matter physics
- Quantum field theory
- Many-body physics
Background:
- The response of noninteracting Fermi gases to magnetic fields is characterized by Fermi volume and Berry curvature.
- Understanding this response in interacting systems is crucial for condensed matter and quantum field theory.
Purpose of the Study:
- To investigate the response of interacting fermion systems to weak static magnetic fields.
- To determine if the characterization of response by Fermi volume and Berry curvature extends to interacting systems.
Main Methods:
- Analysis of fermion density response to a static magnetic field.
- Application of quantum field theory and perturbation theory to all orders.
- Utilizing general analytic properties of quantum field theory.
Main Results:
- The response of interacting fermion systems to a weak static magnetic field is fully characterized by the Fermi volume and Berry curvature.
- This result holds true for both Fermi liquid and non-Fermi liquid states.
- The findings are valid to all orders in perturbation theory.
Conclusions:
- A well-defined Fermi surface and general analytic properties of quantum field theory are sufficient to determine magnetic field response.
- The established characterization of magnetic response is model-independent and universally applicable to interacting fermions.
- This work provides a fundamental understanding of magnetic field effects in diverse fermionic systems.
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