科研之友
微信
新浪微博
Facebook
分享链接
摘要
In the development of quantum information technologies, molecule-based materials with electron spins as the information carrier is considered highly promising due to their outstanding designability and scalability acquired via the vast variety of chemical synthesis, modification and assembling approaches. Throughout the past decade, researchers have managed to achieve great advances in the molecular design and quantum coherent manipulation methods of molecular quantum information materials, but the effort has been mainly at the ensemble level. This article firstly reviews worldwide studies in the recent years dedicated to the following purposes: (1) To clarify the structure-function relation of molecular qubits and to utilize them to synthesis high-performance qubit units, (2) to fabricate multilevel systems, i.e., molecular qudits, that outperform two-level systems in handling more information and accommodating more complicated manipulations, and therefore are more promising regarding potential applications, and (3) to integrate multiple functions, such as response to light or pulse electric field, in magnetic molecular or crystalline systems to enrich the toolbox with which quantum manipulations can be applied. Among these, contributions from the authors’ group are introduced. Any exploration of this kind may be challenged by a common loophole in the underlying concept: While the behavior of an ensemble can represent that of a quantum system to some extent, it cannot be excluded in principle that the behavior is merely an analogue merging from the statistical effect of the sub-ensemble being observed, with the whole ensemble being classical in nature. For this reason and the unavoidable requirement to address single spin centers coupled together to form applicational devices, the authors stress that further research on the molecule-based quantum information materials needs to be carried out on the single-spin level. After discussions about the stages which this process consists of and technical routes and requirements to implement them, it is suggested that optically detected magnetic resonance (ODMR) is a promising option due to its ability to characterize and coherently manipulate single spins given that the spin carrier have spin-selective opto-physical processes. Since most reported ODMR studies focus solely on a specific kind of defect in solid, the need for a spectrometer that are capable of investigating a variety of single molecules are proposed. This article then discusses functions that the spectrometer needs to integrate and specifies a framework composed of the following subsystems: (1) A liquid helium cryostat with high vacuum sample space, (2) a laser confocal microscope to address and initialize the single spin, (3) antibunching single photon detection to validate the single photon nature of the emitter focused on, (4) 3-dimensional nanopositioners to conduct scans and locate the target molecule, (5) a 3-dimensional vector magnet to apply the magnetic field at any direction, (6) a broadband microwave system to cover a large range of resonance frequencies and to apply the coherent manipulation, and (7) a multi-channel arbitrary sequence generator to synchronously control the operation of laser, microwave and detector. In conclusion, with the field of molecule-based quantum information materials being promising in various aspects, the current situation of its development has been indicating a need to enter the regime of single spins and precise characterization and manipulation. The authors expect that the instrumental advancement, along with a new research paradigm constructed by the integration of spin chemistry and quantum information science, may propel the pragmatic development of molecular quantum information technology. ? 2023 Chinese Academy of Sciences.
- 单位
