Orbital Feshbach Resonance: A "Wide" Narrow Resonance for Higher Transition Temperature Fermi Superfluid

TL;DR

This paper demonstrates that the orbital Feshbach resonance in Yb-173 is a narrow energy resonance with a wide magnetic field range, enabling higher transition temperatures for Fermi superfluids, especially on the BCS side.

Contribution

It reveals that the orbital Feshbach resonance in Yb-173 is a narrow energy resonance with a broad magnetic field width, facilitating the realization of high-temperature Fermi superfluids.

Findings

Higher transition temperature at the BCS side due to narrow resonance

Resonance is narrow in energy but wide in magnetic field

Encourages experimental realization of superfluid in Yb-173 system

Abstract

In this letter we show that the recently theoretically predicted and experimentally observed "orbital Feshbach resonance" in alkali-earth-like Yb-173 atom is a narrow resonance in energy, while it is hundreds Gauss wide in term of magnetic field strength, taking the advantage that the magnetic moment difference between the open and closed channels is quite small. Therefore this is an ideal platform for the experimental realization of a strongly interacting Fermi superfluid with narrow resonance. We show that the transition temperature for the Fermi superfluid in this system, especially at the BCS side of the resonance, is even higher than that in a wide resonance, which is also due to the narrow character of this resonance. Our results will encourage experimental efforts to realize Fermi superfluid in the alkali-earth-like Yb-173 system, the properties of which will be complementary to extensively studied Fermi superfluids nearby a wide resonance in alkali K-40 and Li-6 systems.