ELFT HÍRADÓ

[Kormos Márton <kormos.marton AT ttk.bme.hu>]

MEGHÍVÓ

BME Elméleti Fizika Szeminárium,

ápr. 24. péntek 10h15,

1111 Budapest, Budafoki út 8., BME F III. magasföldszint 01.,
Elméleti Fizika Tanszék szemináriumi szoba

Kolok Baksa (BME Elméleti Fizika Tanszék)
RING: Rabi oscillations induced by nonresonant geometric drive

Coherent control of two-level quantum systems is typically achieved using 
resonant driving fields, forming the basis for qubit operations. Here, we 
report a mechanism for inducing complete Rabi oscillations in 
monochromatically driven two-level quantum systems, when the drive frequency 
is much larger than the Larmor frequency of the qubit [1]. This effect—Rabi 
oscillations induced by nonresonant geometric drive (RING)—requires that the 
control field is elliptical, enclosing a nonzero area per cycle. We 
illustrate the effect with numerical simulations, and provide an analytical 
understanding via a simple effective Hamiltonian obtained from Floquet theory 
[2] and perturbation theory [3]. We show that RING enables coherent 
oscillations without relying on resonant energy exchange, allows for 
high-pass noise filtering, provides access to non-Abelian phases in nonzero 
magnetic fields. We detail a realization in electrically driven spin-orbit 
qubits and argue that the RING mechanism enables amplification of the Rabi 
frequency using the same gate voltage amplitudes at higher drive frequencies. 
Our results broaden the landscape of quantum control techniques, by 
highlighting a pathway to achieving coherent oscillations under off-resonant 
driving conditions.

[1] Baksa Kolok, András Pályi, RING: Rabi oscillations induced by nonresonant 
geometric drive, arXiv:2602.11979 [cond-mat.mes-hall]
[2] J. H. Shirley, Solution of the Schrödinger equation with a Hamiltonian 
periodic in time, Phys. Rev. 138, B979 (1965).
[3] R. Winkler, Appendix B: Quasi-degenerate perturbation theory, in 
Spin-orbit coupling effects in two-dimensional electron and hole systems 
(Springer Berlin, Heidelberg, Berlin, Heidelberg, 2003) pp. 201–205.

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Kormos Márton,
szemináriumi koordinátor