Heating-Induced Long-Range η Pairing in the Hubbard Model

Area of Science:

• Condensed Matter Physics
• Quantum Mechanics
• Statistical Mechanics

Background:

• The Hubbard model is a fundamental model in condensed matter physics describing interacting electrons in a lattice.
• Understanding the behavior of quantum systems at high temperatures, particularly in non-equilibrium steady states, is crucial for developing new quantum technologies.
• Long-range correlations are key features in many exotic quantum phases of matter, including superconductivity.

Purpose of the Study:

• To investigate the emergence of long-range correlations in the Hubbard model when its spin degrees of freedom are heated to infinite temperature.
• To explore whether these correlations are dependent on the specific mechanism used to induce heating (dissipation or periodic driving).
• To connect these findings to previously identified superconducting eigenstates.

Main Methods:

• Simulating the Hubbard model under conditions of infinite temperature heating.
• Employing both dissipative and periodic driving methods to induce heating.
• Analyzing the resulting non-equilibrium steady states for the presence of long-range correlations.

Main Results:

• Heating the spin degrees of freedom to infinite temperature leads to the creation of steady states with long-range correlations between eta pairs.
• These steady states are achieved through either dissipation or periodic driving, melting all spin order.
• The emergent steady state exhibits distance-invariant off-diagonal eta correlations, consistent with Yang's superconducting eigenstates.

Conclusions:

• The observed long-range correlations are a universal consequence of the system's symmetries, not specific microscopic details.
• The findings demonstrate a general mechanism for creating exotic quantum states in driven or dissipative systems.
• This work provides a new perspective on non-equilibrium quantum phenomena and their relation to fundamental symmetries.