Adiabatic rapid passage (ARP) is a powerful technique for efficient transfer of population between quantum states. In the laboratory, the efficiency of ARP is often limited by noise on either the energies of the states or the frequency of the driving field. We study ARP in the simple setting of a two-level system subject to sinusoidal fluctuations on the energy level separation by numerically solving the optical Bloch equations in the absence of damping. We investigate the dependence of the efficiency of population transfer on the frequency and amplitude of the perturbation and find that it is predominantly affected by resonant coupling when the detuning matches the frequency of the noise. We present intuitive principles for when ARP becomes inefficient within this model, and provide a sufficient condition for the population transfer to be above an arbitrary threshold.
Adiabatic rapid passage (ARP) is a powerful technique for efficient transfer of population between quantum states. In the laboratory, the efficiency of ARP is often limited by noise on either the energies of the states or the frequency of the driving field. We study ARP in the simple setting of a two-level system subject to sinusoidal fluctuations on the energy level separation by numerically solving the optical Bloch equations in the absence of damping. We investigate the dependence of the efficiency of population transfer on the frequency and amplitude of the perturbation and find that it is predominantly affected by resonant coupling when the detuning matches the frequency of the noise. We present intuitive principles for when ARP becomes inefficient within this model, and provide a sufficient condition for the population transfer to be above an arbitrary threshold.
Adiabatic rapid passage (ARP) is extensively used to achieve efficient transfer or inversion of populations in quantum systems. Landau and Zener accurately estimated the transfer probability of ARP for a closed system and showed that this probability improved with higher drive amplitude. Recently, we found that, in open quantum systems, applying a strong drive can give rise to significant drive-induced dissipation (DID). Here, we investigate the effect of DID on the performance of ARP that is implemented using a linearly chirped pulse on a two-level system. From the Landau-Zener formula, the population transfer was known to be enhanced with increasing drive amplitude. However, here we show that, beyond a threshold value of the drive amplitude, the transfer probability is reduced because of the detrimental effect of DID. We show that the competition between the two processes results in an optimal behavior of the population transfer. We also propose a phenomenological model that helps explain such nonmonotonic behavior of the transfer. Using this model, we estimate the optimum time at which the maximum population transfer occurs. We extend the analysis for rectangular as well as Gaussian pulse profiles and conclude that a Gaussian pulse outperforms a rectangular pulse.
Abstract : When an electromagnetic field, coupling two levels of an atomic or molecular system, has its frequency swept across resonance, population reversal can occur as a result of the coherent transient phenomenon known as adiabatic rapid passage (ARP). For this phenomenon to occur, the frequency sweep rate is required to be rapid with respect to the relaxation processes occuring in the system, and at the same time slow enough so that the system can follow the frequency sweep adiabatically. The present investigations treat ARP in the 87Rb hyperfine transition, where optical pumping produces a population imbalance in the ground-state hyperfine levels, and where the influence of a microwave frequency swept across the hyperfine resonance is monitored by the transmitted intensity of the optical pumping laser. These parameters relate to how adiabatic and how rapid the passage through resonance must be in order to maximize the degree of population reversal. We find both experimentally and theoretically that the adiabaticity requirement is rather weak, and that once satisfied, it is more important to pass through the resonance rapidly. Furthermore, interpreting our results in the Bloch vector model f ARP, we find that the Block vector is only required to precess a half revolution about the effective field in order to follow a 90 degree change in the direction of that field. The applicability of the present results of ARP in general is discussed. Originator supplied keywords include: Adiabatic rapid passage, Atomic line shapes, Quantum mechanics.
We have developed a simple and physically clear picture of adiabatic rapid passage (ARP) in molecules in solution by careful examination of all the conditions needed for ARP. The relaxation effects were considered in the framework of the Landau-Zener model for random crossing of levels. The model enables us to include into consideration non-Markovian Gaussian-correlated noise. It explains all the numerical results obtained in the first paper of the series [B. D. Fainberg and V. A. Gorbunov, J. Chem. Phys. 117, 7222 (2002)], in particular, that for positive chirp pulse excitation relaxation favors more efficient population transfer with respect to the relaxation-free system with frozen nuclear motion. We also relate parameters of non-Markovian Gaussian-correlated noise with irreversible dephasing time of an optical transition by calculating the photon echo signal attenuation.
We consider performing adiabatic rapid passage (ARP) using frequency-swept driving pulses to excite a collection of interacting two-level systems. Such a model arises in a wide range of many-body quantum systems, such as cavity QED or quantum dots, where a nonlinear component couples to light. We analyze the one-dimensional case using the Jordan-Wigner transformation, as well as the mean-field limit where the system is described by a Lipkin-Meshkov-Glick Hamiltonian. These limits provide complementary insights into the behavior of many-body systems under ARP, suggesting our results are generally applicable. We demonstrate that ARP can be used for state preparation in the presence of interactions, and identify the dependence of the required pulse shapes on the interaction strength. In general, interactions increase the pulse bandwidth required for successful state transfer, introducing new restrictions on the pulse forms required.
The shortcut to adiabaticity (STA) is a powerful technique to speed up population transfer via quantum coherent control. This paper demonstrates that STA provides a fast, robust, and efficient population transfer compared to the stimulated Raman adiabatic passage. In the ideal situation of a closed system, STA is insensitive to the detunings and Rabi frequencies, and the undesired diabatic transitions could be eliminated by the auxiliary pulses, so the complete population transfer from the initial state to the target state in the designed adiabatic passage can be rapidly achieved against the inevitable amplitude noises of the interactions and systematic errors. When we consider the situation including the environment noises, spontaneous emission from the intermediate state $|2\ensuremath{\rangle}$ in STA can be sufficiently ignored in the cases of the dark-state evolution and quantum overdamping, since the state $|2\ensuremath{\rangle}$ is thoroughly separated from the three-state system. Moreover, the diabatic transitions induced by the spontaneous emission are also sufficiently suppressed in STA.
Coherent population transfer in an atom using a sequence of adiabatic rapid passages through single-photon resonances is well-known, but it requires that the frequency sweep match the changing frequencies of the atomic transitions. The same population transfer can be effected via a single multiphoton adiabatic rapid passage, which requires only a small frequency sweep, if it is possible to select the desired multiphoton transition from the many possible transitions. Here we report the observation of population transfer between Rydberg states by high order multiphoton adiabatic rapid passage.