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MON: Monday Contributed Sessions
MON 2: Quantum Control
MON 2.6: Talk
Monday, September 8, 2025, 15:30–15:45, ZHG002
Counterdiabatic driving for random gap Landau-Zener (LZ) transitions — •Georgios Theologou1, Mikkel F. Andersen2,3, and Sandro Wimberger4,5 — 1ITP, Universität Heidelberg — 2Department of Physics, University of Otago — 3Dodd-Walls Centre for Photonic and Quantum Technologies — 4Department of Mathematical, Physical and Computer Sciences, Parma University — 5INFN, Sezione Milano-Bicocca, Parma group
The LZ model describes a two-level quantum system governed by a time-dependent Hamiltonian which undergoes an avoided crossing. In the adiabatic limit, the transition probability PLZ vanishes. To enforce an adiabatic evolution at arbitrary speed, an auxiliary control field HCD = fCD σ can be reverse-engineered, such that the full Hamiltonian H + HCD drives the states transitionlessly. In the LZ case, fCD takes the form of a Lorentzian pulse centered at the crossing, and the matrix σ is determined by the orthogonality of HCD with HLZ and ḢLZ. Our aim is to construct a single HGCD that controls an ensemble of LZ-type Hamiltonians with a distribution of energy gaps. For a single realization, the evolution is not any more adiabatic nor the final transition probability is zero. HGCD can be optimized to minimize the expectation value of a given cost function. We consider the effect of different sweeps and prefactors fCD. We found a systematic trade-off between instantaneous adiabaticity and the final transition probability. As an analytically solvable limit, we examine the LZ model in the presence of a δ(t) potential and the connection to the minimization of the corresponding non-adiabatic probablity PLZD.
Keywords: Quantum Control; Spectral Noise; Random Gap Distribution; Adiabatic Quantum Computing