Rotor Spectra, Berry Phases, and Monopole Fields: from Antiferromagnets to QCD

Abstract

The order parameter of a finite system with a spontaneously broken continuous global symmetry acts as a quantum mechanical rotor. Both antiferromagnets with a spontaneously broken $SU(2{)}_s$ spin symmetry and massless QCD with a broken $SU(2{)}_L\times SU(2{)}_R$ chiral symmetry have rotor spectra when considered in a finite volume. When an electron or hole is doped into an antiferromagnet or when a nucleon is propagating through the QCD vacuum, a Berry phase arises from a monopole field and the angular momentum of the rotor is quantized in half-integer units.

arXiv comment4 pages

References in corpus (8)

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Cited by in corpus (12)

• Effective Field Theory for Finite Systems with Spontaneously Broken Symmetry
• Effective theory for deformed nuclei
• Effective Field Theory of Emergent Symmetry Breaking in Deformed Atomic Nuclei
• Effective field theory for deformed odd-mass nuclei
• Low-Energy QCD in the Delta Regime
• Non-Abelian Monopole in the Parameter Space of Point-like Interactions
• On the symmetry of the vacuum in theories with spontaneous symmetry breaking
• Antiferromagnetic order in systems with doublet $S_{\mathrm{tot}}=1/2$ ground states
• Broken Symmetry and Fractionalized Flux Strings in a Staggered U(1) Pure Gauge Theory
• Effective field theories for collective excitations of atomic nuclei
• Rotor Spectra and Berry Phases in the Chiral Limit of QCD on a Torus
• Supersymmetry and non-Abelian geometric phase for a free particle on a circle with point-like interactions