Coherent superconductivity with large gap ratio from incoherent metals

Abstract

A mysterious incoherent metallic (IM) normal state with $T$-linear resistivity is ubiquitous among strongly correlated superconductors. Recent progress with microscopic models exhibiting IM transport has presented the opportunity for us to study new models that exhibit direct transitions into a superconducting state out of IM states within the framework of connected Sachdev-Ye-Kitaev (SYK) "quantum dots". Here local SYK interactions within a dot produce IM transport in the normal state, while local attractive interactions drive superconductivity. Through explicit calculations, we find two features of superconductivity arising from an IM normal state: First, despite the absence of quasiparticles in the normal state, the superconducting state still exhibits coherent superfluid transport. Second, the non-quasiparticle nature of the IM Green's functions produces a large enhancement in the ratio of the zero-temperature superconducting gap $\Delta$ and transition temperature $T_{sc}$, $2\Delta /T_{sc}$, with respect to its BCS value of $3.53$.

4 pages, 3 figures + references + appendices. Added analysis of superconducting transition

References in corpus (8)

• Building an AdS/CFT superconductor
• Theory of universal incoherent metallic transport
• Energy gaps in high-transition temperature cuprate superconductors
• Translationally invariant non-Fermi liquid metals with critical Fermi-surfaces: Solvable models
• Scaling theory of the cuprate strange metals
• Magnetotransport in a model of a disordered strange metal
• Dispersive SYK model: band structure and quantum chaos
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Cited by in corpus (34)

• Sachdev-Ye-Kitaev Models and Beyond: A Window into Non-Fermi Liquids
• Theory of a Planckian metal
• Cooper pairing of incoherent electrons: an electron-phonon version of the Sachdev-Ye-Kitaev model
• Large $N$ theory of critical Fermi surfaces
• Exact Superconducting Instability in a Doped Mott Insulator
• Solvable Strong-coupling Quantum Dot Model with a Non-Fermi-liquid Pairing Transition
• Linear resistivity and Sachdev-Ye-Kitaev (SYK) spin liquid behavior in a quantum critical metal with spin-$1/2$ fermions
• A critical strange metal from fluctuating gauge fields in a solvable random model
• Quantum Phase Transition in the Yukawa-SYK Model
• $T$-linear resistivity in models with local self-energy
• Intrinsic superconducting instabilities of a solvable model for an incoherent metal
• Quantum critical Eliashberg theory, the SYK superconductor and their holographic duals
• Superconducting instabilities in a spinful Sachdev-Ye-Kitaev model
• Spontaneous Breaking of $U(1)$ Symmetry in Coupled Complex SYK Models
• Low-energy antiferromagnetic spin fluctuations limit the coherent superconducting gap in cuprates
• SYK Superconductivity: Quantum Kuramoto and Generalized Richardson Models
• Superconductivity of incoherent electrons in Yukawa-SYK model
• Two-stage superconductivity in the Hatsugai-Kohmoto-BCS model
• Solvable model for a charge-$4e$ superconductor
• Superconducting critical temperature in the extended diffusive SYK model
• Linear-in-$T$ resistivity from semiholographic non-Fermi liquid models
• Superconductor--Insulator Transition in a non-Fermi Liquid
• Thermal effects in non-Fermi liquid superconductivity
• Solvable Theory of a Strange Metal at the Breakdown of a Heavy Fermi Liquid
• Planckian superconductor
• Superconductivity of non-Fermi liquids described by Sachdev-Ye-Kitaev models
• A Simple Solvable Model for Heavy Fermion Superconductivity from the Two-Fluid Normal State
• Mimicking black hole event horizons in atomic and solid-state systems
• Thermodynamics and dynamics of coupled complex SYK models
• Wormhole-induced effective coupling in SYK chains
• Superconducting gap ratio from strange metal phase in the absence of quasiparticles
• An effective framework for strange metallic transport
• Superlinear Hall angle and carrier mobility from non-Boltzmann magnetotransport in the spatially disordered Yukawa-Sachdev-Ye-Kitaev model on a square lattice
• The extended diffusive Sachdev-Ye-Kitaev model as a sort of "strange metal"