The technique of stimulated Raman adiabatic passage (STIRAP), which allows efficient and selective population transfer between quantum states without suffering loss due to spontaneous emission, was introduced in 1990 (Gaubatz \emph{et al.}, J. Chem. Phys. \textbf{92}, 5363, 1990). Since then STIRAP has emerged as an enabling methodology with widespread successful applications in many fields of physics, chemistry and beyond. This article reviews the many applications of STIRAP emphasizing the developments since 2000, the time when the last major review on the topic was written (Vitanov \emph{et al.}, Adv. At. Mol. Opt. Phys. \textbf{46}, 55, 2001). A brief introduction into the theory of STIRAP and the early applications for population transfer within three-level systems is followed by the discussion of several extensions to multi-level systems, including multistate chains and tripod systems. The main emphasis is on the wide range of applications in atomic and molecular physics (including atom optics, cavity quantum electrodynamics, formation of ultracold molecules, precision experiments, etc.), quantum information (including single- and two-qubit gates, entangled-state preparation, etc.), solid-state physics (including processes in doped crystals, nitrogen-vacancy centers, superconducting circuits, etc.), and even some applications in classical physics (including waveguide optics, frequency conversion, polarization optics, etc.). Promising new prospects for STIRAP are also presented (including processes in optomechanics, detection of parity violation in molecules, spectroscopy of core-nonpenetrating Rydberg states, and population transfer with X-ray pulses).

Stimulated Raman adiabatic passage in physics, chemistry, and beyond

Today, Surface Acoustic Waves (SAWs) and Bulk Acoustic Waves (BAW) are already two of the very few phononic technologies of industrial relevance and can been found in a myriad of devices employing these nanoscale earthquakes on a chip. Acoustic radio frequency filters, for instance, are integral parts of wireless devices. SAWs in particular find applications in life sciences and microfluidics for sensing and mixing of tiny amounts of liquids. In addition to these continuously growing number of applications, SAWs are ideally suited to probe and control elementary excitations in condensed matter at the limit of single quantum excitations. Even collective excitations, classical or quantum, or integrated optomechanical are nowadays coherently interfaced by SAWs.

This wide, highly diverse, interdisciplinary and continuously expanding spectrum literally unites advanced sensing and manipulation applications. Remarkably, SAW technology is inherently multiscale and span from single atomic or nanoscopic units up even to the millimeter scale.

The aim of this roadmap article is to present a snapshot of the present state of Surface Acoustic Wave science and technology in 2019 and provide an opinion on the challenges and opportunities that the future holds from a group of renown experts covering the interdisciplinary key areas, ranging from fundamental quantum effects to practical applications of acoustic devices in life science.

/pdf/the-2019-surface-acoustic-waves-roadmap-1krdj88d0z.pdf

The 2019 surface acoustic waves roadmap

We control the electronic structure of the silicon-vacancy (SiV) color-center in diamond by changing its static strain environment with a nano-electro-mechanical system This allows deterministic and local tuning of SiV optical and spin transition frequencies over a wide range, an essential step towards multiqubit networks In the process, we infer the strain Hamiltonian of the SiV revealing large strain susceptibilities of order 1 PHz/strain for the electronic orbital states We identify regimes where the spin-orbit interaction results in a large strain susceptibility of order 100 THz/strain for spin transitions, and propose an experiment where the SiV spin is strongly coupled to a nanomechanical resonator

Strain engineering of the silicon-vacancy center in diamond

Hybrid spin-mechanical systems provide a platform for integrating quantum registers and transducers. Efficient creation and control of such systems require a comprehensive understanding of the individual spin and mechanical components as well as their mutual interactions. Point defects in silicon carbide (SiC) offer long-lived, optically addressable spin registers in a wafer-scale material with low acoustic losses, making them natural candidates for integration with high quality factor mechanical resonators. Here, we show Gaussian focusing of a surface acoustic wave in SiC, characterized by a novel stroboscopic X-ray diffraction imaging technique, which delivers direct, strain amplitude information at nanoscale spatial resolution. Using ab initio calculations, we provide a more complete picture of spin-strain coupling for various defects in SiC with C3v symmetry. This reveals the importance of shear for future device engineering and enhanced spin-mechanical coupling. We demonstrate all-optical detection of acoustic paramagnetic resonance without microwave magnetic fields, relevant to sensing applications. Finally, we show mechanically driven Autler-Townes splittings and magnetically forbidden Rabi oscillations. These results offer a basis for full strain control of three-level spin systems.

Probing spin-phonon interactions in silicon carbide with Gaussian acoustics

Hybrid spin–mechanical systems provide a platform for integrating quantum registers and transducers. Efficient creation and control of such systems require a comprehensive understanding of the individual spin and mechanical components as well as their mutual interactions. Point defects in silicon carbide (SiC) offer long-lived, optically addressable spin registers in a wafer-scale material with low acoustic losses, making them natural candidates for integration with high-quality-factor mechanical resonators. Here, we show Gaussian focusing of a surface acoustic wave in SiC, characterized using a stroboscopic X-ray diffraction imaging technique, which delivers direct, strain amplitude information at nanoscale spatial resolution. Using ab initio calculations, we provide a more complete picture of spin–strain coupling for various defects in SiC with C3v symmetry. This reveals the importance of shear strain for future device engineering and enhanced spin–mechanical coupling. We demonstrate all-optical detection of acoustic paramagnetic resonance without microwave magnetic fields, relevant for sensing applications. Finally, we show mechanically driven Autler–Townes splittings and magnetically forbidden Rabi oscillations. These results offer a basis for full strain control of three-level spin systems. The authors use surface acoustic waves, focused in a Gaussian geometry, to manipulate the spin state of divacancy defects in silicon carbide via mechanical driving. They demonstrate that shear strain is important in controlling the spin transitions.

/pdf/spin-phonon-interactions-in-silicon-carbide-addressed-by-53383tx5tv.pdf

Spin–phonon interactions in silicon carbide addressed by Gaussian acoustics

We demonstrate optomechanical quantum control of a nitrogen vacancy (NV) in the resolved-sideband regime by coupling the NV to both optical fields and surface acoustic waves and by using strong excited-state electron-phonon coupling for NVs.

/pdf/optomechanical-quantum-control-of-a-nitrogen-vacancy-center-1oaygbor0o.pdf

Optomechanical quantum control of a nitrogen vacancy center in diamond

Coupling artificial atoms and acoustic waves may be key in future quantum information processing efforts. An experimental breakthrough in coupling nitrogen vacancy centers strongly to acoustic waves in a way that still preserves their spin coherence is reported.

https://link.aps.org/pdf/10.1103/PhysRevX.6.041060

Coupling a Surface Acoustic Wave to an Electron Spin in Diamond via a Dark State

The emerging field of quantum acoustics explores interactions between acoustic waves and artificial atoms and their applications in quantum information processing. In this experimental study, we demonstrate the coupling between a surface acoustic wave (SAW) and an electron spin in diamond by taking advantage of the strong strain coupling of the excited states of a nitrogen vacancy center, while avoiding the short lifetime of these states. The SAW-spin coupling takes place through a lamda-type three-level system where two ground spin states couple to a common excited state through a phonon-assisted as well as a direct dipole optical transition. Both coherent population trapping and optically-driven spin transitions have been realized. The coherent population trapping demonstrates the coupling between a SAW and an electron spin coherence through a dark state. The optically-driven spin transitions, which resemble the sideband transitions in a trapped ion system, can enable the quantum control of both spin and mechanical degrees of freedom and potentially a trapped-ion-like solid state system for applications in quantum computing. These results establish an experimental platform for spin-based quantum acoustic, bridging the gap between spintronics and quantum acoustics.

Coupling a Surface Acoustic Wave to an Electron Spin in diamond via a Dark State

We report theoretical studies of adiabatic population transfer using dressed spin states. Quantum optimal control using the algorithm of Chopped Random Basis (CRAB) has been implemented in a negatively charged diamond nitrogen vacancy center that is coupled to a strong and resonant microwave field. We show that the dressed spin states are highly effective in suppressing effects of spin dephasing on adiabatic population transfer. The numerical simulation also demonstrates that CRAB-based quantum optimal control can enable an efficient and robust adiabatic population transfer.

/pdf/adiabatic-population-transfer-of-dressed-spin-states-with-21n75nenzu.pdf

Adiabatic population transfer of dressed spin states with quantum optimal control

A strain-induced lambda-type three-level system in a nitrogen vacancy center in diamond is used for the implementation of shortcut to adiabatic passage through a dark state with counterdiabatic driving.

Mayra Amezcua

Papers

Optomechanical quantum control of a nitrogen vacancy center in diamond

Coupling a Surface Acoustic Wave to an Electron Spin in Diamond via a Dark State

Coupling a Surface Acoustic Wave to an Electron Spin in diamond via a Dark State

Adiabatic population transfer of dressed spin states with quantum optimal control

Shortcut to adiabaticity for an electron spin in diamond