PhD student, Yiou Zhang, has received the Graduate Instrumentation Research Award (GIRA). ​

The GIRA program aims to encourage and facilitate greater involvement of physics graduate students in significant instrumentation development, to boost recognition of instrumentation work as a vital part of PhD training, to foster growth of future HEP instrumentation experts in the US, and to strengthen university-lab ties on instrumentation development. GIRA has been established by the Coordination Panel for Advanced Detectors (CPAD), a standing committee of The Division of Particles and Fields of the American Physical Society. Each year, one proposal will be recommended for funding to the Department of Energy's Office of High Energy Physics. 

The project that will be sponsored by the Graduate Instrumentation Research Award (GIRA) is to develop an ultra-sensitive and ultrafast magnetic tunneling junctions (MTJ) sensor array, which can operate under low temperature and high magnetic field and serve as a detector of weak magnetic fields, such as those that could arise from nuclear spins in a nuclear magnetic resonance (NMR) experiment. A Magnetic Tunnel Junction, which utilizes the tunneling-magneto-resistance effect, is an ultra-sensitive magnetic sensor with high spatial and temporal resolution. Such quantum coherent tunneling effect not only increases the sensitivity of MTJ sensors, but also provides more readily accessible observations of quantum correlation effects. This makes MTJ sensors very suitable for incorporating with other techniques such as NMR for the search of axions, dark matter candidate. Moreover, NMR control of nuclear spins can allow us to perform measurements with sensitivity approaching the quantum limit. Broadly speaking, the MTJ sensor could also permit us to implement effective probes of interactions that break time-reversal symmetry (TRS), such as those that could give rise to the electric dipole moment beyond the standard model. 

To adapt the MTJ for axion detection, i.e. interactions that break TRS, an MTJ sensor must have a high sensitivity as well as low intrinsic noise.  Therefore, technical aspect of this work will focus on low-temperature intrinsic noise measurements. Electronic noise can play a uniquely informative role in discovering new physics - noise fluctuations in time of a measurement can contain information that is not present in the time-averaged value. Moreover, noise probes quantum fluctuations, by its very nature, and hence is a key source of information about the physics arising from quantum interactions. Our aim is to improve sensitivity of MTJ so that it can only limited by the fundamental laws of quantum mechanics.  Concepts for quantum information science (QIS) applications of NMR as well as recently proposed Flouquet enhanced measurements (achieved by the application of complex RF-pulse sequences) will be applied to perturb/drive spin systems and so develop direct probes of relevant quantum correlations. 

To enable this multidisciplinary work, Yiou will take advantage of the well developed collaborative research atmosphere at Brown Physics department.  He will be supervised by his advosor, Professor Gang Xiao (leader in spintronics research) on fabrication of MTJ sensors and sensitivity optimizations; Professor Vesna Mitrović (Condensed matter experiment (CME), QIS) in whose laboratory the MTJ-based dark matter search experiment will be carried out using the NMR technique; Professor Ulrich Heintz (HEP-instrumentation expert) on the development of the signal read-out and conditioning circuit; Professor Jia Li (CME - 2D graphene based devices); Professors Dima Feldman and Brad Marston (QIS, quantum sensing, theory).