Extra cost of erasure due to quantum lifetime broadening

TL;DR

This paper investigates the fundamental and practical limits of erasing information in quantum dot systems, revealing that nonequilibrium effects and energy level broadening increase the minimal work required beyond classical bounds.

Contribution

It introduces a thermodynamic framework for quantum dot information erasure, accounting for nonequilibrium conditions and energy level broadening effects.

Findings

Potential difference and lifetime broadening increase erasure cost

Nonequilibrium electrode conditions significantly affect thermodynamic limits

Practical erasure costs can exceed classical Landauer bound

Abstract

The energy cost of erasing a bit of information was fundamentally lower bounded by Landauer, in terms of the temperature of its environment: $W\geq k_\mathrm{B} T \ln 2$. However, in real electronic devices, the information-bearing system is usually in contact with two or more electrodes, with different temperatures and chemical potentials. It is not clear what sets the cost of erasure in such nonequilibrium situations. One promising technology for testing the thermodynamic limits of information processing is quantum dots, in which a bit is encoded in the presence or absence of a single electron. We here develop a thermodynamic description of devices of this type and find that, in addition to the electrode temperatures, the potential difference across the quantum dot and lifetime broadening of its energy level contribute to the minimum work cost of erasure. In practical contexts, these contributions may significantly outweigh the cost due to temperature alone.