One-dimensional fermions with neither Luttinger-liquid nor Fermi-liquid behavior

Area of Science:

• Condensed Matter Physics
• Quantum Mechanics
• Many-Body Physics

Background:

• One-dimensional interacting fermions typically exhibit Tomonaga-Luttinger liquid behavior, not Fermi liquid properties.
• Key characteristics of Tomonaga-Luttinger liquids include ill-defined Landau quasiparticles and continuous fermion occupation number at the Fermi energy.

Purpose of the Study:

• To demonstrate the stabilization of a novel state of one-dimensional matter through fine-tuning fermion interactions.
• To introduce and characterize this new state, termed the quasi-Fermi liquid.
• To explore its unique properties that differ from both Tomonaga-Luttinger and Fermi liquids.

Main Methods:

• Renormalization group analysis to determine the conditions for the quasi-Fermi liquid state (irrelevant fermion interaction).
• Theoretical investigation of the properties of the proposed quasi-Fermi liquid.
• Discussion of potential experimental realization using cold atoms in optical traps.

Main Results:

• A quasi-Fermi liquid state can be stabilized in one-dimensional systems with specific fermion interactions.
• This state lacks finite-momentum quasiparticles, similar to Tomonaga-Luttinger liquids.
• It exhibits a finite discontinuity in fermion occupation number at the Fermi energy, a characteristic of Fermi liquids.

Conclusions:

• The quasi-Fermi liquid represents a distinct phase of matter, bridging characteristics of Tomonaga-Luttinger and Fermi liquids.
• This discovery expands the understanding of quantum phenomena in one-dimensional interacting fermion systems.
• The proposed realization with cold atoms suggests potential avenues for experimental verification.