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Hira Ali

Publications and source records attributed to Hira Ali.

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Complexity and Information in Quantum and Classical Trajectories

We analyze emission trajectories from a driven-dissipative two-qubit system and a classical telegraph model with matched rates. Using Lempel-Ziv complexity, mutual information, and temporal correlations, we show that both models undergo a transition from independent to synchronized dynamics as coupling increases, but only the quantum trajectories develop enhanced complexity and sustained information sharing at large drive-to-decay ratio. Classical correlations are short-lived and quickly suppressed by strong drive. A strong complexity-information correlation appears uniquely in the quantum case, providing a clear trajectory-level signature of quantum effects. These results show that complexity and information measures extracted directly from jump records provide an efficient way to distinguish quantum and classical dynamics in open systems.

quant-ph

Electrostatic tuning of bilayer graphene edge modes

We study the effect of a local potential shift induced by a side electrode on the edge modes at the boundary between gapped and ungapped bilayer graphene. A potential shift close to the gapped-ungapped boundary causes the emergence of unprotected edge modes, propagating in both directions along the boundary. These counterpropagating edge modes allow edge backscattering, as opposed to the case of valley-momentum-locked edge modes. We then calculate the conductance of a bilayer graphene wire in presence of finger-gate electrodes, finding strong asymmetries with energy inversion and deviations from conductance quantization that can be understood with the gate-induced unprotected edge modes.

cond-mat.mes-hall

Quantum walk on a ladder

We study quantum walk on a ladder with combination of conventional and split-step protocols. The two components of the walk resulting from periodic boundary conditions can be made to have three kinds of probability distributions. Two of these are the one-sided and alternative ones. Using the differences between coin states of the individual component, we can simulate the third case in which both components have identical probability profiles. We also observe that the mutual information transfer between two components of the walk is minimized when this difference across the two sides of the ladder is maximized.

quant-ph