https://doi.org/10.1140/epjb/s10051-024-00725-0
Regular Article - Solid State and Materials
The impact of different unravelings in a monitored system of free fermions
1
Dipartimento di Matematica e Informatica, Università di Catania, Viale Andrea Doria 6, 95125, Catania, Italy
2
Dipartimento di Fisica dell’Università di Pisa & INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127, Pisa, Italy
3
Dipartimento di Fisica “E. Pancini”, Università di Napoli Federico II, Complesso di Monte S. Angelo, via Cinthia, 80126, Naples, Italy
Received:
14
February
2024
Accepted:
7
June
2024
Published online:
25
June
2024
We consider a free-fermion chain undergoing dephasing, described by two different random-measurement protocols (unravelings): a quantum-state-diffusion and a quantum-jump one. Both protocols keep the state in a Slater-determinant form, allowing to address quite large system sizes. We find a bifurcation in the distribution of the measurement operators along the quantum trajectories, that’s to say, there is a point where the shape of this distribution changes from unimodal to bimodal. The value of the measurement strength where this phenomenon occurs is similar for the two unravelings, but the distributions and the transition have different properties reflecting the symmetries of the two measurement protocols. We also consider the scaling with the system size of the inverse participation ratio of the Slater-determinant components and find a power-law scaling that marks a multifractal behaviour, in both unravelings and for any nonvanishing measurement strength.
© The Author(s) 2024
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