Population transfer between two quantum states by piecewise chirping of femtosecond pulses: theory and experiment

We propose and experimentally demonstrate the method of population transfer by piecewise adiabatic passage between two quantum states. Coherent excitation of a two-level system with a train of ultrashort laser pulses is shown to reproduce the effect of an adiabatic passage, conventionally achieved with a single frequency-chirped pulse. By properly adjusting the amplitudes and phases of the pulses in the excitation pulse train, we achieve complete and robust population transfer to the target state. The piecewise nature of the process suggests a possibility for the selective population transfer in complex quantum systems.     

Experimental demonstration of selective coherent population transfer via a continuum

We report the first experimental demonstration of coherent population transfer, induced by stimulated Raman adiabatic passage, via continuum states. Population is transferred from the metastable state 2s(1)S(0) to the excited state 4s(1)S(0) in helium atoms in a two-photon process mediated by coherent interaction with the ionization continuum. While incoherent techniques usually do not permit any population transfer in such a process, we show that stimulated Raman adiabatic passage allows significant population transfer to take place also via ultrafast decay channels.     

Nonleaky Population Transfer in a Transmon Qutrit via Largely-Detuned Drivings

We propose an efficient scheme to implement nonleaky population transfer in a transmon qutrit via largely-detuned drivings. Due to weak level anharmonicity of the transmon system, the remarkable quantum leakages need to be considered in quantum coherent operations. Under the conditions of two-photon resonance and large detunings, the robust population transfer within a qutrit can be implemented via the technique of stimulated Raman adiabatic passage. Based on the accessible parameters, the feasible approach can remove the leakage error effectively, and then provides a potential approach for enhancing the transfer fidelity with transmon-regime artificial atoms experimentally.     

Piecewise adiabatic passage with a series of femtosecond pulses

We develop a method of executing complete population transfers between quantum states in a piecewise manner using a series of femtosecond laser pulses. The method can be applied to a large class of problems as it benefits from the high peak powers and large spectral bandwidths afforded by femtosecond pulses. The degree of population transfer is robust to a wide variation in the absolute and relative intensities, durations, and time ordering of the pulses. The method is studied in detail for atomic sodium where piecewise adiabatic population transfer, as well as the induction of Ramsey-type interferences, is demonstrated.     

Efficient population transfer by delayed pulses despite coupling ambiguity

In traditional schemes of multilevel multilaser excitation, each laser pulse interacts with only one pair of states, and the rotating wave approximation (RWA) is applicable. Here we study the population transfer process in a three-state system when each of the two lasers interacts with each of the pair of states and when the Rabi frequencies characterizing the interaction strengths of the system are comparable to or larger than the difference of the transition frequencies. We show that complete and robust population transfer is possible under conditions more general than those hitherto considered necessary for stimulated Raman adiabatic passage (STIRAP) or for successive π pulses. Using adiabatic Floquet theory we show that successful population transfer can be interpreted as adiabatic passage by means of a transfer state which connects the initial and final states. The Floquet picture offers a convenient interpretation of the population transfer as accompanied by multiple absorption of photons from or emission into the laser fields.     

Robust population transfer by stimulated raman adiabatic passage in a Pr3+:Y2SiO5 crystal

We report on the experimental implementation of stimulated Raman adiabatic passage (STIRAP) in a Pr3+:Y2SiO5 crystal. Our data provide clear and striking proof for nearly complete population inversion between hyperfine levels in the Pr3+ ions. The transfer efficiency was monitored by absorption spectroscopy. Time-resolved absorption measurements serve to monitor the adiabatic population dynamics during the STIRAP process. Efficient transfer is observed for negative pulse delays (STIRAP), as well as for positive delays. We identify the latter by an alternative adiabatic passage process.     

A comparison of NCO and NCA transfer methods for biological solid-state NMR spectroscopy

Three different techniques (adiabatic passage Hartman-Hahn cross-polarization, optimal control designed pulses, and EXPORT) are compared for transferring (15)N magnetization to (13)C in solid-state NMR experiments under magic-angle-spinning conditions. We demonstrate that, in comparison to adiabatic passage Hartman-Hahn cross-polarization, optimal control transfer pulses achieve similar or better transfer efficiencies for uniformly-(13)C,(15)N labeled samples and are generally superior for samples with non-uniform labeling schemes (such as 1,3- and 2-(13)C glycerol labeling). In addition, the optimal control pulses typically use substantially lower average RF field strengths and are more robust with respect to experimental variation and RF inhomogeneity. Consequently, they are better suited for demanding samples.     

Chirped-pulse adiabatic control in coherent anti-Stokes Raman scattering for imaging of biological structure and dynamics

Two novel control methods based on adiabatic passage are proposed to be implemented in coherent anti-Stokes Raman scattering (CARS) microscopy for noninvasive imaging of biological structure and dynamics. The first method provides optimal pulse-area control of the resonant vibrational transitions by using a pair of equally linear-chirped pulses. The second method, named the 'roof' method, utilizes the chirp sign variation at the central time and gives robust adiabatic excitation of the resonant vibrational mode. Both methods are robust with respect to suppression of the off-resonant transitions. The methods allow one to achieve chemical sensitivity with high resolution and can be used to obtain CARS spectra of biological molecules with efficiently suppressed background.     

Sensitivity to parameters of STIRAP in a Cooper Pair Box

The rapid experimental progress in the field of superconducting nanocircuits gives rise to an increasing quest for advanced quantum-control techniques for these macroscopically coherent systems. Here we demonstrate theoretically that stimulated Raman adiabatic passage (STIRAP), a well-established method in quantum optics, should be possible with the quantronium setup of a Cooper-pair box. We find the parameters which optimize the procedure and show how the scheme appears to be robust against decoherence and should be realizable even with the existing technology.     

Generation of atomic entangled states in a bi-mode cavity via adiabatic passage

We propose schemes to prepare atomic entangled states in a bi-mode cavity via stimulated Raman adiabatic passage (STIRAP) and fractional stimulated Raman adiabatic passage (f-STIRAP) techniques. Our scheme should be realizable in the near future because of the existence of all experimental ingredients. Our numerical simulation shows we can entangle the atoms with high fidelities by choosing proper laser pulses.     

Acoustic topological adiabatic passage via a level crossing

Stimulated adiabatic passage has been extensively studied to achieve robust and selective population transfer in quantum systems. Recently, the quantum-classic analogy has been rapidly developing and can be considered responsible for the implementation of the adiabatic transfer of sound energy in cavity chain systems. In this article, we investigate the adiabatic transfer of sound energy between two topological end states in the Su-Schrieffer-Heeger(SSH) cavity chain, which can be considered to be the acoustic analog of the quantum chirped-pulse excitation. The topological adiabatic passage in SSH cavity chain has two categories. When the single-cavity resonance frequencies on the sublattices A and B in the SSH cavity chain do not switch their spectrum positions, the topologically protected adiabatic evolution results in the returning passage of the sound excited in one end cavity. When a level crossing with single-cavity resonance frequencies on the sublattices A and B exhibits switch in the frequency spectrum, acoustic energy is observed to be topologically pumped between the two end cavities of the SSH chain.     

Quantum gates and multiparticle entanglement by Rydberg excitation blockade and adiabatic passage

We propose to apply stimulated adiabatic passage to transfer atoms from their ground state into Rydberg excited states. Atoms a few micrometers apart experience a dipole-dipole interaction among Rydberg states that is strong enough to shift the atomic resonance and inhibit excitation of more than a single atom. We show that the adiabatic passage in the presence of this interaction between two atoms leads to robust creation of maximally entangled states and to two-bit quantum gates. For many atoms, the excitation blockade leads to an effective implementation of collective-spin and Jaynes-Cummings-like Hamiltonians, and we show that the adiabatic passage can be used to generate collective J_{x}=0 eigenstates and Greenberger-Horne-Zeilinger states of tens of atoms.     

Three-Dimensional Quantum State Transferring Between Two Remote Atoms by Adiabatic Passage under Dissipation

Recently, Zhou et al. [Phys. Rev. A 79 （2009） 044304] proposed a scheme for transferring three-dimensional quantum states between remote atomic qubits confined in cavities connected by fibers through adiabatic passage. In order to avoid the decoherence due to spontaneous emission, Zhou et al. utilized the large detuning atom-field interaction. In the present paper, we discuss the influence of dissipation on the scheme in both the resonant atom-field interaction case and the large detuning case. We numerically analyze the success probability and the transferring fidelity. It is shown that the resonant case is a preferable choice for the technique of the stimulated Raman adiabatic passage （STIRAP） due to the shorter operation time and the smaller probability of dissipation.     

Effective inhibit energetic cost in stimulated Raman shortcut-to-adiabatic passage

A shortcut to the adiabatic process is an effective method for quantum information processing.The fast and robust quantum information transfer can be implemented by this method.The energetic cost is an important measurement for the shortcut.In this paper,we investigate how to inhibit the energetic cost in stimulated Raman shortcut-to-adiabatic passage in a three-level system.The energetic cost can be manipulated by adjusting detuning of the system and the energetic cost takes the minimum with one-photon resonance condition.     

Ultrafast coherent population transfer driven by two few-cycle laser pulses

We investigate ultrafast coherent population transfer driven by few-cycle pump and Stokes laser pulses in the Λ-type three-level system with the stimulated Raman adiabatic passage technique beyond the rotating-wave approximation. In contrast to the case with the rotating wave approximation, the most efficient population transfer may be realized without the satisfaction of the one-photon resonances or two-photon resonance and the transfer efficiency depends critically on the Rabi frequencies and initial optical phases of the two laser fields when the peak Rabi frequencies are much larger than the respective transition frequencies. Moreover, complete and robust population transfer can still be obtained with the variations of the Rabi frequencies, pulse durations, and one-photon or two-photon detuning in a moderate range, though a considerable transient population may reside in the excited state. These abnormal behaviors result from the counterrotating terms, which are not taken into account in the traditional rotating wave approximation.     

Quantum information transfer with Cooper-pair box qubits in circuit QED

We propose a feasible scheme to transfer quantum information with Cooper-pair box qubits arrayed in a circuit QED. Qubits interact with a quantum data bus generated by a one-dimensional transmission line resonator. Based on the Raman adiabatic passage, the cavity bus-assisted quantum population transfer between any selected pair of qubits can be controlled by addressing the applied gate pulses. Therefore, the scheme provides the possibility for effectively implementing scalable quantum information transfer with Josephson devices.     

Wireless adiabatic power transfer

We propose a technique for efficient mid-range wireless power transfer between two coils, by adapting the process of adiabatic passage for a coherently driven two-state quantum system to the realm of wireless energy transfer. The proposed technique is shown to be robust to noise, resonant constraints, and other interferences that exist in the neighborhood of the coils.     

Quantum state engineering in ion-traps via adiabatic passage

We propose two relatively robust schemes to generate entangled W states of three (or generally N) ions in ion trap systems by using adiabatic passage technique and appropriately designed ion-field couplings in a single step. In the first scheme, we apply the N-pod fractional stimulated Raman adiabatic passage (F-STIRAP) technique to generate W state of N ions using two Gaussian laser pulses. We also show that the W state of N ? 1 ions can be created via a simple N-pod standard STIRAP by two laser pulses. In the second scheme, we generate the entangled state of N ions via ??-pulse technique by a single laser pulse. We also study the population transfer of the system by numerical solutions of the master equation, considering the effect of decoherence channels due to laser intensity fluctuations and dissipation in the phonon modes.     

Preparation of Fock states and quantum entanglement via stimulated Raman adiabatic passage using a four-level atom

We study the behaviour of an atom-cavity system exposed to a stimulated Raman adiabatic passage (STIRAP) process in a four-level system, with a coupling scheme which generate two degenerate dark states. We find that the non-adiabatic interaction of the two dark states guarantees that the cavity Fock states can always be generated by both intuitively and counterintuitively ordered pulses. Furthermore, we propose a method to entangle two atoms. Depending on the ordering of the pulses two orthogonal entangled states can be prepared. Since these entangled states do not have component of the excited states included, the technique is robust against the detrimental consequences of spontaneous emission. Received 20 March 2001