High-Fidelity Adiabatic Passage by Composite Sequences of Chirped Pulses

Abstract

We present a method for optimization of the technique of adiabatic passage between two quantum states by composite sequences of frequency-chirped pulses with specific relative phases: composite adiabatic passage (CAP). By choosing the composite phases appropriately the nonadiabatic losses can be canceled to any desired order with sufficiently long sequences, regardless of the nonadiabatic coupling. The values of the composite phases are universal for they do not depend on the pulse shapes and the chirp. The accuracy of the CAP technique and its robustness against parameter variations make CAP suitable for high-fidelity quantum information processing.

Broadband composite polarization rotator

“…Such half-wave plates allow for imperfect rotary power ϕ/L and deviations in the plate thickness L, and furthermore, operate over a wide range of wavelengths λ. To achieve this, we will follow an analogous approach to that of composite pulses [12][13][14][15], which is widely adopted for robust control in quantum physics [17][18][19]. In detail, we replace the single half-wave plate with an arrangement of an odd number N = 2n + 1 half-wave plates (shown schematically in Fig.1).…”

Pulse design without the rotating-wave approximation

“…Controlling accurately the internal states of quantum two-level systems, realized by real or artificial atoms, as in crystal defects, quantum dots, or superconducting qubits, is a fundamental task in nuclear magnetic resonance, metrology or to develop new quantum technologies [1][2][3][4][5][6][7][8][9]. Pulse engineering is the art and science of designing realizable control fields to perform specific operations.…”

Robust coherent superposition of states using quasiadiabatic inverse engineering

“…[1,2,3,4,5,6] An important class of coherent manipulation involves the production of robust superpositions of states [7,8,9]. For two-level systems, there are several techniques for coherent manipulation of the states of a quantum system, for example, π-pulses [1], composite pulses [10,11,12,13], optimal control theory (OCT) techniques [14,15], and adiabatic techniques [3,6,16]. In general, π-pulses are fast but highly sensitive to variations in pulse parameters.…”