Low-temperature transport in Heisenberg chains

Area of Science:

• Condensed Matter Physics
• Quantum Mechanics
• Statistical Mechanics

Background:

• Understanding transport properties of quantum systems is crucial.
• Quantum-spin chains exhibit complex behaviors at finite temperatures.
• Distinguishing between integrable and nonintegrable systems is key to predicting their properties.

Purpose of the Study:

• To present a quantum Monte Carlo technique for accurate transport property determination.
• To evaluate the impact of interactions on Drude weight in integrable systems.
• To investigate the effect of nonintegrability on Drude weight in gapless quantum-spin chains.

Main Methods:

• Quantum Monte Carlo simulations.
• Analysis of transport properties at finite temperatures.
• Comparison of integrable and nonintegrable quantum-spin chain models.

Main Results:

• Accurate determination of transport properties for quantum-spin chains.
• Quantification of Drude weight reduction due to interactions in integrable systems.
• Evidence for the absence of Drude weight in nonintegrable gapless systems with long-range interactions.

Conclusions:

• The developed technique reliably assesses transport properties.
• Interactions significantly affect Drude weight in integrable regimes.
• Nonintegrability plays a critical role in the transport characteristics of quantum-spin chains.