Accelerating quantum information transfer in a three-level system via a specified intermediate Hamiltonian

Abstract We propose a general approach to speed up quantum adiabatic processes for fast quantum information transfer in a three-level system. In the approach, by using an intermediate Hamiltonian which is assumed to be formed by the original Hamiltonian <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>H</mml:mi> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> </mml:msub> <mml:mo stretchy="false">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> and its counterdiabatic driving Hamiltonian <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>H</mml:mi> <mml:mtext>cd</mml:mtext> </mml:msub> <mml:mo stretchy="false">(</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> with a simple linear relationship, we design exact dynamics following the eigenstates of the intermediate Hamiltonian to speed up the desired population processes. We apply the present approach to a three-level system to show that by suitably choosing the parameters, not only the population processes could be sped up, but also the existence of the undesired off-diagonal terms, the populations of the intermediate states, and even the shapes of the pulses would be controllable in the speeding up scheme.