Speeding up Adiabatic Quantum State Transfer by Using Dressed States

Abstract

We develop new pulse schemes to significantly speed up adiabatic state transfer protocols. Our general strategy involves adding corrections to an initial control Hamiltonian which harness nonadiabatic transitions. These corrections define a set of dressed states that the system follows exactly during the state transfer. We apply this approach to STIRAP protocols and show that a suitable choice of dressed states allows one to design fast protocols that do not require additional couplings, while simultaneously minimizing the occupancy of the "intermediate" level.Introduction -The general goal of moving quantum states between two different systems finds numerous applications in quantum information processing [1,2]. It has generated intense theoretical interest, with numerous approaches developed to allow high fidelity state transfer that are robust against dissipation and noise. Among the more powerful and interesting strategies are adiabatic transfer protocols [3]. These generically involve adiabatically evolving an eigenstate of a composite quantum system, such that the state is initially localized in the "source" system and ends up being localized in the "target" system (see Fig. 1(a)). The adiabatic evolution thus corresponds to a state transfer, with the initial state of the source system "riding" the adiabatic eigenstates, and ending up in the target system. The most famous examples of such approaches are the STIRAP [4] and CTAP [5] protocols, well known in atomic physics.

Shortcuts to adiabaticity in the presence of a continuum: Applications to itinerant quantum state transfer

“…Such protocols have been discussed in systems ranging from atomic cavity QED setups [31,32] to optomechanics [34]. Remarkably, we show that our method works even in the highly constrained protocol introduced by Duan et al [32], where there is only a single time-dependent control field in the Hamiltonian.Our work represents a substantial advance over previous work using STA to accelerate adiabatic state transfer [20][21][22][23][24][25], as these works did not include a coupling to a continuum. It also differs significantly from studies ex-…”

“…Our work represents a substantial advance over previous work using STA to accelerate adiabatic state transfer [20][21][22][23][24][25], as these works did not include a coupling to a continuum. It also differs significantly from studies ex- (a) Three level Λ system with time-dependent couplings G1(t), G2(t).…”

“…A key drawback of the transitionless driving strategy and its higher order variants [20][21][22][23][24][25] is that they require the exact diagonalization of a time-dependent Hamiltonian, making them unwieldy for systems with many degrees of freedom. They are thus unsuitable for an important class of quantum state transfer problems, where the goal is to transfer an initial state in a localized system having discrete energy levels to a propagating state in a continuum such as a waveguide or a transmission line (see, e.g., [31][32][33]).…”

“…These techniques are generally referred to as "shortcuts to adiabaticity" (STA), and involve modifying control fields to suppress the net effect of non-adiabatic errors [20][21][22][23][24][25]. Recent experiments have successfully implemented versions of these strategies [26][27][28][29][30].A key drawback of the transitionless driving strategy and its higher order variants [20][21][22][23][24][25] is that they require the exact diagonalization of a time-dependent Hamiltonian, making them unwieldy for systems with many degrees of freedom. They are thus unsuitable for an important class of quantum state transfer problems, where the goal is to transfer an initial state in a localized system having discrete energy levels to a propagating state in a continuum such as a waveguide or a transmission line (see, e.g., [31][32][33]).…”

“…There is thus considerable interest in finding ways to accelerate adiabatic protocols, such that fast evolution is possible without significant non-adiabatic errors [15][16][17][18][19]. These techniques are generally referred to as "shortcuts to adiabaticity" (STA), and involve modifying control fields to suppress the net effect of non-adiabatic errors [20][21][22][23][24][25]. Recent experiments have successfully implemented versions of these strategies [26][27][28][29][30].…”