News
New Paper: “nanoSQUID operation using kinetic rather than magnetic induction”
We report on a method of nanoSQUID modulation which uses kinetic inductance rather than magnetic inductance to manip-ulate the internal fluxoid state. We produced modulation using injected current rather than an applied magnetic field. Using this injected current, we were able to observe the triangle-wave shaped modulation of the device critical current which was periodic according to the London fluxoid quantization condition. The measurement results also confirmed that the fluxoid state inside a superconducting loop can be manipulated using primarily kinetic inductance. By using primarily kinetic inductance rather than magnetic inductance, the size of the coupling inductor was reduced by a factor of 10. As a result, this approach may provide a means to reduce the size of SQUID-based superconducting electronics. Additionally, this method provides a convenient way to perform kinetic inductance characterizations of superconducting thin films.
Seeking post-doctoral candidate in superconducting nanowires
Post-doctoral candidate sought with experience suitable for performing research in one or more of the following areas: superconducting electronics/detectors, low temperature physics, applications of superconducting devices, and related research topics. The post-doc will have an opportunity to develop superconducting-nanowire-based devices and apply them to quantum information science, energy-efficient classical computation, and the study of superconducting physics, as well as the opportunity to collaborate on other ongoing and new projects in our research group. The new hire will assist in planning and management of group activities, especially in mentoring graduate and undergraduate students, planning and executing research programs, and raising funds for research. The candidate must have a Ph.D. in Electrical Engineering, Applied Physics, or a related field. The initial emphasis of the work will be on the development superconducting circuits based on nanowire cryotrons for applications to superconducting memories and optical-electronic interfaces. Applications to single-photon will also be investigated.
Interested candidates may apply at http://goo.gl/forms/mleVXYlfWydeymej2. If this link is unavailable to you for any reason (some geographic locations block google forms), you may contact Dorothy Fleischer (dotf@mit.edu) for assistance in completing the form. Applications will be evaluated as received, with a candidate selection and appointment expected in the Fall of 2016.
Andrew Dane awarded MRS symposium student presentation prize at MRS Spring 2016
Congratulations to QNN member Andrew Dane for being awarded the MRS symposium student presentation prize for his talk “Bias Sputtered Few-Nanometer-Thick Niobium Nitride for Superconducting Devices” at the Spring 2016 Materials Research Society meeting in Phoenix. He presented in the symposium “Tailoring Superconductors—Materials and Devices from Basic Science to Applications.”
Emily Toomey awarded NSF fellowship
Congratulations to Emily Toomey on receiving the National Science Foundation Graduate Research Fellowship. This prestigious and competitive award will support her work for three years.
New Paper: “Designs for a quantum electron microscope”
One of the astounding consequences of quantum mechanics is that it allows the detection of a target using an incident probe, with only a low probability of interaction of the probe and the target. This ‘quantum weirdness’ could be applied in the field of electron microscopy to generate images of beam-sensitive specimens with substantially reduced damage to the specimen. A reduction of beam-induced damage to specimens is especially of great importance if it can enable imaging of biological specimens with atomic resolution. Following a recent suggestion that interaction-free measurements are possible with electrons, we now analyze the difficulties of actually building an atomic resolution interaction-free electron microscope, or “quantum electron microscope”. A quantum electron microscope would require a number of unique components not found in conventional transmission electron microscopes. These components include a coherent electron beam-splitter or two-state-coupler, and a resonator structure to allow each electron to interrogate the specimen multiple times, thus supporting high success probabilities for interaction-free detection of the specimen. Different system designs are presented here, which are based on four different choices of two-state-couplers: a thin crystal, a grating mirror, a standing light wave and an electro-dynamical pseudopotential. Challenges for the detailed electron optical design are identified as future directions for development. While it is concluded that it should be possible to build an atomic resolution quantum electron microscope, we have also identified a number of hurdles to the development of such a microscope and further theoretical investigations that will be required to enable a complete interpretation of the images produced by such a microscope.
“Designs for a quantum electron microscope.” P. Kruit, R.G. Hobbs, C-S. Kim, Y. Yang, V.R. Manfrinato, J. Hammer, S. Thomas, P. Weber, B. Klopfer, C. Kohstall, T. Juffmann, M.A. Kasevich, P. Hommelhoff, K.K. Berggren. Ultramicroscopy, Available online 10 March 2016, ISSN 0304-3991, http://dx.doi.org/10.1016/j.ultramic.2016.03.004.