Abstract This topical review addresses how Rydberg atoms can serve as building blocks for emerging quantum technologies. Whereas the fabrication of large numbers of artificial quantum systems with the uniformity required for the most attractive applications is difficult if not impossible, atoms provide stable quantum systems which, for the same species and isotope, are all identical. Whilst atomic ground states provide scalable quantum objects, their applications are limited by the range over which their properties can be varied. In contrast, Rydberg atoms offer strong and controllable atomic interactions that can be tuned by selecting states with different principal quantum number or orbital angular momentum. In addition Rydberg atoms are comparatively long-lived, and the large number of available energy levels and their separations allow coupling to electromagnetic fields spanning over 6 orders of magnitude in frequency. These features make Rydberg atoms highly desirable for developing new quantum technologies. After giving a brief introduction to how the properties of Rydberg atoms can be tuned, we give several examples of current areas where the unique advantages of Rydberg atom systems are being exploited to enable new applications in quantum computing, electromagnetic field sensing, and quantum optics.
Abstract This topical review addresses how Rydberg atoms can serve as building blocks for emerging quantum technologies. Whereas the fabrication of large numbers of artificial quantum systems with the uniformity required for the most attractive applications is difficult if not impossible, atoms provide stable quantum systems which, for the same species and isotope, are all identical. Whilst atomic ground states provide scalable quantum objects, their applications are limited by the range over which their properties can be varied. In contrast, Rydberg atoms offer strong and controllable atomic interactions that can be tuned by selecting states with different principal quantum number or orbital angular momentum. In addition Rydberg atoms are comparatively long-lived, and the large number of available energy levels and their separations allow coupling to electromagnetic fields spanning over 6 orders of magnitude in frequency. These features make Rydberg atoms highly desirable for developing new quantum technologies. After giving a brief introduction to how the properties of Rydberg atoms can be tuned, we give several examples of current areas where the unique advantages of Rydberg atom systems are being exploited to enable new applications in quantum computing, electromagnetic field sensing, and quantum optics.
This topical review addresses how Rydberg atoms can serve as building blocks for emerging quantum technologies. Whereas the fabrication of large numbers of artificial quantum systems with the uniformity required for the most attractive applications is difficult if not impossible, atoms provide stable quantum systems which, for the same species and isotope, are all identical. Whilst atomic ground-states provide scalable quantum objects, their applications are limited by the range over which their properties can be varied. In contrast, Rydberg atoms offer strong and controllable atomic interactions that can be tuned by selecting states with different principal quantum number or orbital angular momentum. In addition Rydberg atoms are comparatively long-lived, and the large number of available energy levels and their separations allow coupling to electromagnetic fields spanning over 6 orders of magnitude in frequency. These features make Rydberg atoms highly desirable for developing new quantum technologies. After giving a brief introduction to how the properties of Rydberg atoms can be tuned, we give several examples of current areas where the unique advantages of Rydberg atom systems are being exploited to enable new applications in quantum computing, electromagnetic field sensing, and quantum optics.
Since the discovery of the Rydberg atom in 1885, research on the Rydberg atom has presented numerous discoveries about the Rydberg atom. As the atoms has valence electron in a high principal quantum number state, Rydberg atoms can interact with each other in a unique way, such as dipole-dipole interactions, Rydberg blockade and anti-blockade. To reach the Rydberg state, it is usually necessary to use a laser to excite the atoms from their ground state. Due to the special characteristics about Rydberg atoms as well as their interactions, it has demonstrated promising of application in different fields, for example, quantum computing and quantum information, as well as nonlinear optics and photonics. However, due to the technical limitations, the demand of deterministic atoms sources and the effect of blackbody radiation are still hindering the research relative to Rydberg atoms. For future study relative to Rydberg atoms, the additions with laser-trapping could be beneficial for fields like quantum electro dynamics and localized electromagnetic field probing.
Rydberg atoms are neutral atoms excited to high principal quantum number states, which endows them with exaggerated properties such as large electric dipole moments, long lifetimes, and extreme sensitivity to external electromagnetic fields. These characteristics form the foundation of Rydberg atom-based sensors, an emerging class of quantum devices capable of optically detecting electric fields across frequencies from DC to the terahertz regime. Rydberg-based electrometry operates through both Autler–Townes (AT) splitting of resonant Rydberg transitions and Stark-shift measurements for high-frequency or far-detuned fields, enabling broadband field sensing from DC to the THz regime. Using ladder-type electromagnetically induced transparency (EIT) and AT splitting, these sensors enable non-invasive, SI-traceable measurements of field amplitude, frequency, phase, and polarization. Recent developments have demonstrated broadband electric field probes, voltage calibration standards, and compact RF receivers based on thermal vapor cells and integrated photonic architectures. Furthermore, innovations in multi-photon EIT, superheterodyne readout, and multi wave mixing have expanded the dynamic range and bandwidth of Rydberg-based electrometry. Despite challenges related to environmental perturbations, linewidth broadening, and laser stabilization, ongoing advances in atomic control, hybrid photonic integration, and EIT-based readout promise scalable, chip-compatible sensors. This review summarizes the physical principles, experimental progress, and emerging applications of Rydberg atom-based sensing, emphasizing their potential for next generation quantum metrology, wireless communication, and precision field mapping.
This introductory chapter presents the scope of this book: namely that the book is devoted to Rydberg (i.e., highly-excited) atoms and molecules They have striking distinctions to atoms and molecules in the ground or low-excited states. For Rydberg atoms, with the increase of the principal quantum number n, their characteristic size and the electric dipole moment scales as n 2 (which is why they are extremely sensitive to even weak electric fields and electromagnetic radiation) and their radiative lifetime scales as n 3. They strongly interact not only with an electric field, but also with each other: their dipole–dipole interaction scales as n 4/R 3 and their van der Waals interaction scales as n 11/R 6, where R is their separation from each other. In laboratory conditions experimentalists deal with Rydberg atoms having the quantum number of several tens. In the Universe, in H II regions, the principal quantum number of Rydberg atoms can reach n ~ 1000. In the latter case, the Rydberg atoms cannot be considered anymore as microscopic objects: the diameter of their electron orbit is ~ 0.1 mm, i.e., twice the diameter of human hair. Studies of Rydberg atoms and molecules have numerous applications. Examples are highly-responsive sensing, quantum optics (where the light is manipulated at the level of a single photon), quantum computing, quantum chaos, ultracold Rydberg gases and plasmas, anti-hydrogen formation, and plasma diagnostics.
Abstract Rydberg states have become essential in neutral-atom quantum computing as a way of coupling otherwise weakly interacting qubits. Storing information in relatively stable, compact ground states while using large excited states as temporary interaction resources is one of the key lessons that atomic Rydberg physics offers to other quantum platforms. Semiconductor spin qubits provide a very different route to quantum information processing. Their appeal lies in their small footprint, long spin coherence, compatibility with mature fabrication techniques, and potential integration with classical electronics. However, semiconductor architectures also face challenges: interactions are often short-ranged, individual addressing and wiring become increasingly complex at scale, and devices are sensitive to disorder, interfaces, strain, and charge noise. These difficulties motivate the search for other mechanisms that can enhance coupling or provide new readout and control channels without sacrificing advantages. Dopant-bound Rydberg states offer one such possibility. Shallow donors and acceptors in semiconductors possess hydrogenic excited states whose spatial extent and electric-dipole moments are much larger than those of their ground states. These states can be accessed by THz radiation and have already been studied extensively through impurity spectroscopy and, more recently, coherent-control experiments. In analogy with neutral-atom platforms, they need not serve as long-lived qubits themselves. Rather, they may act as auxiliary states that temporarily enhance interactions or provide new qubit control and readout pathways. In this chapter, we review dopant-bound Rydberg states from this perspective.
The interaction of many-body quantum system is a critical problem to be solved in the field of quantum information science. Rydberg atoms have large dipole moment, enabling them to interact with others in a long range, thereby offering us a powerful tool for studying many-body quantum physics. Meanwhile, atoms in the ground state are stable, which makes it easy to manipulate them. Therefore, Rydberg-atom many-body system is an ideal platform for studying the interaction of many-body quantum system. Studies of Rydberg-atom many-body system may contribute to understanding the properties of many-body system and putting the interaction of many-body quantum system into practical applications. In this review, we introduce some studies of properties of interaction of Rydberg-atom many-body system, including the Rydberg excitation blockade, the variation of Rabi frequencies of the many-body system and special spatial distribution of Rydberg atoms in a many-body system. Firstly, the Rydberg excitation blockade, the most important property in the Rydberg-atom many-body system, indicates that atoms’ excitation will be suppressed in a certain range around one Rydberg excitation because the interaction between the Rydberg excitation and atoms leads the energy level to shift so that atoms cannot be excited by the same pulse. Secondly, there is a collective Rabi frequency in the system, which is proportional to the square of the number of atoms in the suppressed area. And additionally, because of the Rydberg blockade effect, Rydberg excitations in the ensemble cannot be at casual positions but a regular distribution is formed. Besides the studies of properties, several researches on the applications of interaction of Rydberg-atom many-body system are introduced, including single-photon source, quantum storage, single-atom imaging, quantum simulation, etc. These applications contribute to the development of quantum community and quantum computing, which may bring us a quantum-technology time. Finally, we discuss the future development of Rydberg-atom many-body system and its further applications. Further development includes the development of many-body system with a larger number of atoms, the development of many-body system of atoms with more than one electron, and some other specific subjects based on many-system, such as Rydberg dimer and topological phase. Also some promising applications such as in studying optimization problem by quantum annealing, may become true.