FutureSearch paper
Summary
The paper investigates the spin conductivity distribution in disordered quantum spin chains, demonstrating that while the average conductivity suggests metallicity, the typical conductivity indicates an insulating state.
Review
This research explores the complex transport properties of one-dimensional disordered spin systems, focusing on the spin-1/2 and spin-1 chains. The authors use a strong-disorder renormalization group (SDRG) approach to analyze the frequency-dependent spin conductivity, revealing a critical insight: the distribution of conductivity becomes increasingly broad at low frequencies.
The key contribution lies in resolving an apparent contradiction between previous predictions of a metallic spin phase and the known localized behavior of these systems. By carefully examining the distribution of conductivity—rather than just its average value—the researchers show that the typical (geometric average) conductivity vanishes, indicating an insulating state, even though the arithmetic average suggests metallicity.
Key Points
- The conductivity distribution becomes extremely broad at low frequencies
- Typical conductivity suggests an insulating state, contrary to average conductivity
- Results apply to spin-1/2 and spin-1 disordered quantum spin chains