Stimulated Raman adiabatic passage (STIRAP) is an important technique to manipulate quantum states in quantum simulation and quantum computation. The transformation fidelity is limited in reality due to experimental imperfections. After systematically calculating the influence of dissipation caused by thermal fluctuations and instantaneous decay of the intermediate state, we find optimized control pulses of Rydberg atom in optical tweezer to increase the STIRAP fidelity via optimal control method. All constraints of currently available control lasers have been taken into account. The transition error can be further depressed when control lasers with shorter rise time and accordingly proper total evolution time are applied. Finally, the robustness of the control pulses with respect to random deviations between the theoretical pulse shape and the implemented ones is also enhanced by additional rounds of optimizations based on ensemble averaged fidelity.
Stimulated Raman adiabatic passage (STIRAP) is an important technique to manipulate quantum states in quantum simulation and quantum computation. The transformation fidelity is limited in reality due to experimental imperfections. After systematically calculating the influence of dissipation caused by thermal fluctuations and instantaneous decay of the intermediate state, we find optimized control pulses of Rydberg atom in optical tweezer to increase the STIRAP fidelity via optimal control method. All constraints of currently available control lasers have been taken into account. The transition error can be further depressed when control lasers with shorter rise time and accordingly proper total evolution time are applied. Finally, the robustness of the control pulses with respect to random deviations between the theoretical pulse shape and the implemented ones is also enhanced by additional rounds of optimizations based on ensemble averaged fidelity.
Accurate control of a quantum system is a fundamental requirement in many areas of modern science ranging from quantum information processing to high-precision measurements. A significantly important goal in quantum control is preparing a desired state as fast as possible, with sufficiently high fidelity allowed by available resources and experimental constraints. Stimulated Raman adiabatic passage (STIRAP) is a robust way to realize high-fidelity state transfer but it requires a sufficiently long operation time to satisfy the adiabatic criteria. Here we theoretically propose and then experimentally demonstrate a shortcut-to-adiabatic protocol to speed-up the STIRAP. By modifying the shapes of the Raman pulses, we experimentally realize a fast and high-fidelity stimulated Raman shortcut-to-adiabatic passage that is robust against control parameter variations. The all-optical, robust and fast protocol demonstrated here provides an efficient and practical way to control quantum systems.
We propose a method to improve the stimulated Raman adiabatic passage (STIRAP) via dissipative quantum dynamics, taking into account the dephasing effects. Fast and robust population transfer can be obtained with the scheme by the designed pulses and detuning, even though the initial state of the system is imperfect. With a concrete three-level system as an example, the influences of the imperfect initial state, variations in the control parameters, and various dissipation effects are discussed in detail. The numerical simulation shows that the scheme is insensitive to moderate fluctuations of experimental parameters and the relatively large dissipation effects of the excited state. Furthermore, the dominant dissipative factors, namely, the dephasing effects of the ground states and the imperfect initial state are no longer undesirable, in fact, they are the important resources to the scheme. Therefore, the scheme could provide more choices for the realization of the complete population transfer in the strong dissipative fields where the standard stimulated Raman adiabatic passage or shortcut schemes are invalid.
Stimulated Raman adiabatic passage (STIRAP) is a widely-used technique of coherent state-to-state manipulation for many applications in physics, chemistry, and beyond. The adiabatic evolution of the state involved in STIRAP, called adiabatic passage, guarantees its robustness against control errors, but also leads to problems of low efficiency and decoherence. Here we propose and experimentally demonstrate an alternative approach, termed stimulated Raman "user-defined" passage (STIRUP), where a parameterized state is employed for constructing desired evolutions to replace the adiabatic passage in STIRAP. The user-defined passages can be flexibly designed for optimizing different objectives for different tasks, e.g. minimizing leakage error. To experimentally benchmark its performance, we apply STIRUP to the task of coherent state transfer in a superconducting Xmon qutrit. We found that STIRUP completed the transfer more then four times faster than STIRAP with enhanced robustness, and achieved a fidelity of 99.5%, which is the highest among all recent experiments based on STIRAP and its variants. In practice, STIRUP differs from STIRAP only in the design of driving pulses; therefore, most existing applications of STIRAP can be readily implemented with STIRUP.
Accurate control of a quantum system is a fundamental requirement in many areas of modern science ranging from quantum information processing to high-precision measurements. A significantly important goal in quantum control is to prepare a desired state as fast as possible with sufficiently high fidelity allowed by available resources and experimental constraints. Stimulated Raman adiabatic passage (STIRAP) is a robust way to realize high-fidelity state transfer but it requires a sufficiently long operation time to satisfy the adiabatic criteria. We here theoretically propose and then experimentally demonstrate a shortcut-to-adiabatic protocol to speed up the STIRAP. By modifying the shapes of the Raman pulses, we experimentally realize a fast and high-fidelity stimulated Raman shortcut-to-adiabatic passage that is robust against control parameter variations. The all-optical, robust, and fast protocol demonstrated here provides an efficient and practical way to control quantum systems.
Abstract We conduct a systematic study to optimize the stimulated Raman adiabatic passage (STIRAP) processes using Pontryagin’s principle. Pontryagin’s principle enables the incorporation of time- and fidelity-based optimization strategies into the traditional adiabatic processes. By incorporating an integral term of the intermediate state population into the cost function of either evolution time or target state fidelity, we can achieve either time-optimal or high-fidelity state transfer while maintaining minimal intermediate state occupation. This optimization method can also be superior to the shortcuts to adiabaticity control in either transfer speed or state fidelity, depending on the chosen cost function. Our method provides a systematic optimization strategy for the STIRAP process. Moreover, this approach is robust against the decoherence effect of the system caused by its surrounding environment, thereby enhancing the overall control performance and stability.
The stimulated Raman adiabatic passage (STIRAP) shows an efficient technique that accurately transfers population between two discrete quantum states with the same parity, in three-level quantum systems based on adiabatic evolution. This technique has widely theoretical and experimental applications in many fields of physics, chemistry, and beyond. Here, we present a generally robust approach to speed up STIRAP with invariant-based shortcut to adiabaticity. By controlling the dynamical process, we inversely design a family of Hamiltonians that can realize fast and accurate population transfer from the first to the third level, while the systematic error is largely suppressed in general. Furthermore, a detailed trade-off relation between the population of the intermediate state and the amplitudes of Rabi frequencies in the transfer process is illustrated. These results provide an optimal route toward manipulating the evolution of three-level quantum systems in future quantum information processing.