Overcoming the detrimental effect of disorder at the nanoscale is very hard since disorder induces localization and an exponential suppression of transport efficiency. Recently new transport regimes have been studied which have counterintuitive properties. In the first part of the talk we unveil novel and robust quantum transport regimes achievable in nanosystems by exploiting long-range hopping. We demonstrate that in a 1D disordered nanostructure in the presence of long-range hopping, transport efficiency, after decreasing exponentially with disorder at first, is then enhanced by disorder [disorder-enhanced transport (DET) regime] until, counterintuitively, it reaches a disorder-independent transport (DIT) regime, persisting over several orders of disorder magnitude in realistic systems. In the second part we study three paradigmatic 1D models, namely the Harper-Hofstadter-Aubry-André and Fibonacci tight-binding chains, along with the power-banded random matrix model. We show that whenever coherent diffusion is present, transport is exceptionally stable against decoherent noise. A universal dependence of the diffusion coefficient on the decoherence strength is analytically derived: the diffusion coefficient remains almost decoherence-independent until the coherence time becomes comparable with the mean elastic scattering time.
Thus, systems with a quantum diffusive regime could be used to design robust quantum wires. Moreover our results might shed new light on the functionality of many biological systems, which often operate at the border between the ballistic and localized regimes.
References
[1] Disorder-enhanced and disorder-independent transport with long-range hopping: Application to molecular chains in optical cavities, NC Chávez, F Mattiotti, JA Méndez-Bermúdez, F (2021). Borgonovi, GL Celardo, Physical Review Letters 126 (15), 153201
[2] Shielding and localization in the presence of long-range hopping. , G. L. Celardo, R. Kaiser and F. Borgonovi, Phys. Rev. B 94, 144206 (2016).
[3] Cooperative Shielding in Many-Body Systems with Long-Range Interaction , L. Santos, F. Borgonovi and G.L.Celardo, Phys. Rev. Lett. 116, 250402 (2016).-
[4] Lozano-Negro, F. S., Alvarez Navarro, E., Chávez, N. C., Mattiotti, F., Borgonovi, F., Pastawski, H. M., & Celardo, G. L. (2024). Universal stability of coherently diffusive one-dimensional systems with respect to decoherence. Physical Review A, 109(4), 042213.
Participante: Dr. Giuseppe Luca Celardo
Institución: Universidad de Florencia
Fecha y hora: Este evento terminó el Jueves, 09 de Enero de 2025