Frontiers in Quantum Science and Technology最新文献

{"title":"Toward real application of quantum sensing and metrology","authors":"T. Ohshima","doi":"10.3389/frqst.2022.998459","DOIUrl":"https://doi.org/10.3389/frqst.2022.998459","url":null,"abstract":"“Quantum sensing and metrology” is a relatively new research field. However, this research field is growing rapidly because of some outstanding features that pre-existing technologies do not have. We can thus achieve sensing with extremely high sensitivity across wide dynamic ranges, such as magnetic fields and temperature, or extremely accurate measurements of factors such as gravity, time, and position using quantum sensing and metrology. Multiple sensing of magnetic fields and temperature is also one of the attractive features of quantum sensing. In addition, the information with nanometer ranges extracted in local areas can be observed using nanoparticles with quantum sensors since only one spin defect can act as a sensor. These features for quantum sensing and metrology open new doors to a wide variety of fields and, as a result, ideas for new applications beyond our present imagination. Although groundbreaking demonstrations have been previously reported (Kucsko et al., 2013; Tetienne et al., 2017; Thiel et al., 2019), it is difficult to say that technology for quantum sensing andmetrology is well developed at present. The quality of host materials for spin defects that act as quantum sensors should be improved. For example, diamond is a host material for the negatively charged nitrogen-vacancy (NV) center, which is one of the most famous spin defects that acts as a quantum sensor (Balasubramanian et al., 2008). At present, there is no technology to fabricate diamond wafers of large diameters. Besides, we must develop controlling methods for reducing crystal defects, including unintentionally doped impurities, although the quality of diamond substrates improves day by day. Of course, diamond is not only a host material for spin defects but also other materials, such as silicon carbide (SiC), Gallium nitride (GaN), and hexagonal boron nitride (hBN), are expected to be applied to host materials (Ohshima et al., 2018; Gottscholl et al., 2021; Hoang, 2022), and researchers are making a significant effort to improve the quality of suchmaterials. New host materials for spin defects as well as new spin defects themselves will be found in the future and, as a result, the applications of quantum sensing will be expanded to cover a broad range of fields. In addition, it is important to establish methodologies for introducing spin defects in host materials. So far, two major methods are applied to the introduction of such spin defects during crystal growth and energetic particle irradiation (Balasubramanian et al., 2009; Yamamoto et al., 2013). Introducing spin defects during crystal growth has an advantage from the point of view of the quality of spin defects as well as host materials since unexpected residual defects that have a harmful impact on spin defects are also introduced by irradiation. For sensing with extremely high sensitivity, spin defects with OPEN ACCESS","PeriodicalId":108649,"journal":{"name":"Frontiers in Quantum Science and Technology","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126936598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Specialty Grand Challenge: Quantum engineering","authors":"J. García-Ripoll","doi":"10.3389/frqst.2022.1029525","DOIUrl":"https://doi.org/10.3389/frqst.2022.1029525","url":null,"abstract":"During the last century, the term “quantum engineering” has adopted very different meanings. In early appearances it often implied the construction quantum systems—e.g., engineering of optical properties through controlled quantum dynamics (Rosencher et al., 1996), atom-by-atom design of nanostructures (Fernández Rossier, 2013), or hybridization of existing quantum objects (Wallquist et al., 2009)—or to the preparation of specific quantum states—e.g., engineering of intrinsically quantum states in trapped ions (Poyatos et al., 1997) or cavity-QED setups (Haroche, 1999). More recently, the quantum engineering have begun to denote a field of reserach, covering either narrow scopes around quantum information tasks (Smith, 2018; Asfaw et al., 2022) or a very broad description that includes all quantum technologies (Dzurak et al., 2022). In this work we refer to quantum engineering as the field devoted to the fabrication, control and characterization of quantum systems with an intrinsically quantum dynamics. In this sense, quantum engineering traverses all areas of quantum technologies, including communication, computing, simulation, metrology and sensing, and also impacts other areas of basic and applied science, where the control of the quantum dynamics and quantum systems brings out new phenomena. Quantum engineering uses the language of quantum information science as a toolbox to understand and design complex quantum states and quantum operations, but it also builds on the tools from quantum control, quantum optics and many-body physics. Inspired by other areas of engineering, as in the work by Zagoskin (2017), one may structure quantum engineering in a bottom-up approach (c.f. Figure 1), according to the degree of complexity of the objects involved: 1) the design and operation of individual quantum units, 2) the engineering of interactions between such units, 3) the combination of those structures into operational devices for communication, computing or sensing, or new emerging structures, 4) and the creation of interfaces between quantum, classical or hybrid devices according to systems engineering. Alternatively, we can focus on the tasks at hand: 1) fabrication, 2) operation and control, and 3) characterization. In the following text we highlight different challenges in several of these possible subdivisions.","PeriodicalId":108649,"journal":{"name":"Frontiers in Quantum Science and Technology","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121246401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection of infrared light through stimulated four-wave mixing process","authors":"Wei-Hang Zhang, Jing-Yuan Peng, Enze Li, Ying-hao Ye, Lei Zeng, M. Dong, D. Ding, B. Shi","doi":"10.3389/frqst.2022.984638","DOIUrl":"https://doi.org/10.3389/frqst.2022.984638","url":null,"abstract":"Infrared optical measurement has a wide range of applications in industry and science, but infrared light detectors suffer from high costs and inferior performance than visible light detectors. Four-wave mixing (FWM) process allows detection in the infrared range by detecting correlated visible light. We experimentally investigate the stimulated FWM process in a hot 85Rb atomic vapor cell, in which a weak infrared signal laser at 1,530 nm induces the FWM process and is amplified and converted into a strong FWM light at 780 nm, the latter can be detected more easily. We find the optimized single- and two-photon detunings by studying the dependence of the frequency of input laser on the generated FWM light. What’s more, the power gain increases rapidly as the signal intensity decreases, which is consistent with our theoretical analysis. As a result, the power gain can reach up to 500 at a signal laser power of 0.1 μW and the number of detected photons increased by a factor of 250. Finally, we experimentally prove that our amplification process can work in a broad band in the frequency domain by exploring the response rate of our stimulated FWM process.","PeriodicalId":108649,"journal":{"name":"Frontiers in Quantum Science and Technology","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126277915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bistable carbon-vacancy defects in h-BN","authors":"Song Li, Á. Gali","doi":"10.3389/frqst.2022.1007756","DOIUrl":"https://doi.org/10.3389/frqst.2022.1007756","url":null,"abstract":"Single-photon emitters in hexagonal boron nitride have been extensively studied recently. Although unambiguous identification of the emitters is still under intense research, carbon-related defects are believed to play a vital role for the emitter producing zero-phonon lines in the range of 1.6–2.2 eV. In this study, we systematically investigate two configurations of carbon-vacancy defects, VNCB and CNVB, by means of density functional theory calculations. We calculated the reaction barrier energies from one defect to the other to determine relative stability. We find that the barrier energies are charge dependent, and CNVB could easily transform to VNCB in neutral- and positive-charge states while it is stable when negatively charged. Formation energy calculations show that the VNCB is the dominant defect over CNVB. However, neither VNCB nor CNVB has suitable fluorescence spectra that could reproduce the observed ones. Our results indicate that the origin of the 1.6-to-2.2-eV emitters should be other carbon-related configurations.","PeriodicalId":108649,"journal":{"name":"Frontiers in Quantum Science and Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123744076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental validation of the Kibble-Zurek mechanism on a digital quantum computer","authors":"Santiago Higuera-Quintero, F. Rodr'iguez, L. Quiroga, Fernando J. G'omez-Ruiz","doi":"10.3389/frqst.2022.1026025","DOIUrl":"https://doi.org/10.3389/frqst.2022.1026025","url":null,"abstract":"The Kibble-Zurek mechanism (KZM) captures the essential physics of nonequilibrium quantum phase transitions with symmetry breaking. KZM predicts a universal scaling power law for the defect density which is fully determined by the system’s critical exponents at equilibrium and the quenching rate. We experimentally tested the KZM for the simplest quantum case, a single qubit under the Landau-Zener evolution, on an open access IBM quantum computer (IBM-Q). We find that for this simple one-qubit model, experimental data validates the central KZM assumption of the adiabatic-impulse approximation for a well isolated qubit. Furthermore, we report on extensive IBM-Q experiments on individual qubits embedded in different circuit environments and topologies, separately elucidating the role of crosstalk between qubits and the increasing decoherence effects associated with the quantum circuit depth on the KZM predictions. Our results strongly suggest that increasing circuit depth acts as a decoherence source, producing a rapid deviation of experimental data from theoretical unitary predictions.","PeriodicalId":108649,"journal":{"name":"Frontiers in Quantum Science and Technology","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131778524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frontiers in Quantum Science and Technology","authors":"F. Jelezko","doi":"10.3389/frqst.2022.889909","DOIUrl":"https://doi.org/10.3389/frqst.2022.889909","url":null,"abstract":"The recently emerged field of quantum technology is aiming to employ quantum coherence and entanglement for realization of next generation sensors, standards, imaging systems, secure communication and computers. Although applications of quantum technologies cover a broad spectrum and their development stage varies from early demonstrations to commercially available devices, many challenges have been identified. The first includes tailoring materials for quantum technologies, which is playing an essential role in technological applications of quantum science. Solid state systems allowing long coherence time are essential for quantum computation and quantum sensing. Ultrapure materials with tailored isotopic content are important for reaching long coherence time of spin qubits (Awschalom et al., 2013). The ability to place single dopants with high precision and form spin qubits at desired location is essential for both quantum computing and quantum sensing applications (McCallum et al., 2012; Smith et al., 2019). The performance of different types of qubits is usually benchmarked in terms of controllability and coherence time. Usually solid-state systems allow fast control, but exhibit fast decoherence owing to complex environment. It is therefore important to search for new types of qubits combining isolation from environment and access via fast coherent control and readout. Novel approaches combining different quantum systems into build hybrid quantum devices for optimal performance is a promising avenue. Examples of such hybrid approaches are spin systems coupled to superconducting qubits (Kubo et al., 2011) and hybrid nuclear–electronic qubits (Morley et al., 2013). Optimal protocols for quantum technologies requires extension of coherence time of qubits beyond the coherence time of the isolated quantum system. The efficient protection toolkit includes dynamical decoupling (Yang et al., 2011) and quantum error correction (Terhal, 2015) based techniques. Although general principles of qubits protection were developed and tested experimentally in different model environments, it is essential to adapt them to realistic environmental noise. In the field of quantum sensing, it is also essential to combine protections against noise with non-reduced sensing performance. Experimental imperfections can be addressed using optimal control tools (Glaser et al., 2015). The development of efficient quantum algorithms is another growing field belonging to quantum software area. On one hand, it is essential to find problems where a quantum computer can outperform classical computers. On the other hand, it is essential to develop an application scenario for a limited number of qubits (Montanaro, 2016). In addition, in order to develop new algorithms, future work must include discoveries of application scenarios of already known algorithms. Application of quantum Fourier transform for sensing is a promising example of such new applications (Vorobyov et al., 2021","PeriodicalId":108649,"journal":{"name":"Frontiers in Quantum Science and Technology","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130315021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}