Stimulated Raman adiabatic passage in a three-level superconducting circuit.

K. S. Kumar,G. S. Paraoanu,A. Vepsäläinen,S. Danilin

doi:10.1038/ncomms10628

Abstract

The adiabatic manipulation of quantum states is a powerful technique that opened up new directions in quantum engineering—enabling tests of fundamental concepts such as geometrical phases and topological transitions, and holding the promise of alternative models of quantum computation. Here we benchmark the stimulated Raman adiabatic passage for circuit quantum electrodynamics by employing the first three levels of a transmon qubit. In this ladder configuration, we demonstrate a population transfer efficiency >80% between the ground state and the second excited state using two adiabatic Gaussian-shaped control microwave pulses. By doing quantum tomography at successive moments during the Raman pulses, we investigate the transfer of the population in time domain. Furthermore, we show that this protocol can be reversed by applying a third adiabatic pulse, we study a hybrid nondiabatic–adiabatic sequence, and we present experimental results for a quasi-degenerate intermediate level.

Highlights

The adiabatic manipulation of quantum states is a powerful technique that opened up new directions in quantum engineering—enabling tests of fundamental concepts such as geometrical phases and topological transitions, and holding the promise of alternative models of quantum computation
An additional powerful concept is that of adiabatic quantum control, a key component in several proposed models of quantum computation[8,9,10,11,12,13], which in recent times led to the measurement of the Berry phase[14] and its nonabelian generalization[15], and to the observation of topological transitions[16]
The absence of population in the intermediate state is ensured by a two-photon destructive interference on the intermediate level that creates a dark state, while the adiabatic manipulation of the amplitudes of the control fields rotates the dark state from the initial state |0i to the target state |2i

Summary

Introduction

The adiabatic manipulation of quantum states is a powerful technique that opened up new directions in quantum engineering—enabling tests of fundamental concepts such as geometrical phases and topological transitions, and holding the promise of alternative models of quantum computation. We benchmark the stimulated Raman adiabatic passage for circuit quantum electrodynamics by employing the first three levels of a transmon qubit In this ladder configuration, we demonstrate a population transfer efficiency 480% between the ground state and the second excited state using two adiabatic Gaussian-shaped control microwave pulses. The transmon[25] is a capacitively shunted split Cooper pair box coupled dispersively with an electromagnetic coplanar waveguide cavity[26], which allows the non-demolition measurement of its quantum state by monitoring the near-resonant response of the cavity[27] With this device it is not possible to transfer directly the population between the ground state |0i and the second excited state |2i due to the fact that the electric dipole momentum between these two states is vanishingly small. We study the effect of applying STIRAP to a superposition between the ground and the first excited state, and we study experimentally the adiabatic Raman sequence in the case of a split intermediate level

Methods

Results

Conclusion