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Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
Quantum statistical-gauge geometry
1Hanoi National University of Education, Hanoi National University of Education, Department of Physics, 136 Xuan Thuy, Cau Giay, Hanoi, Vietnam and Institute of Natural Sciences, 136 Xuan Thuy, Cau Giay, Hanoi, Vietnam.
We reveal a geometric framework for quantum many-body systems, organizing quantum shift symmetry to simplify complex equilibrium constraints. This geometric approach clarifies thermal Ward identities and reveals new antisymmetry relations and positivity bounds.
Area of Science:
- Condensed Matter Physics
- Quantum Field Theory
- Statistical Mechanics
Background:
- Exact equilibrium constraints like sum rules and Ward identities are difficult to analyze in quantum many-body systems due to distributional local currents and anomaly-like contact terms in commutators.
- Existing methods struggle to systematically expose these constraints, hindering a complete understanding of system dynamics.
Purpose of the Study:
- To present a novel geometric organization of quantum shift symmetry in many-body systems.
- To reformulate hyperforces as covariant derivatives and force balance as a thermal Ward identity using the Kubo-Mori inner product.
- To establish a framework for deriving iterative, all-orders constraints and positivity bounds.
Main Methods:
- Viewing the local shifting superoperator as a statistical-gauge connection.
- Proving bulk flatness for compact smearings, showing generators close on a Lie bracket of vector fields without bulk Schwinger terms.
- Quantizing the diffeomorphism moment map to fix the microscopic generator, ensuring agreement between Weyl and half-density quantization.
Main Results:
- A Ward-Bianchi hierarchy of equal-time constraints derived from the closure of smeared shift generators.
- Demonstration of bulk connection flatness, leading to antisymmetry relations and positivity bounds.
- Analysis of how background electromagnetic fields deform the algebra via density-weighted curvature insertions, not bulk central extensions.
Conclusions:
- The geometric framework provides a powerful tool for understanding equilibrium constraints in quantum many-body systems.
- Global topology influences the system through holonomy, connecting to twisted boundary conditions and flux threading.
- The framework is successfully applied to fractional quantum Hall fluids, linking to the GMP-W_{∞} algebra and verified through exact diagonalization.
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