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Author Amundsen, Morten; Linder, Jacob url  openurl
  Title General solution of 2D and 3D superconducting quasiclassical systems: coalescing vortices and nanodisk geometries Type Journal Article
  Year 2015 Publication arXiv:1512.00030 [cond-mat.supr-con] Abbreviated Journal  
  Volume Issue Pages  
  Keywords quasiclassical Usadel equation, finite elements method  
  Abstract (up) In quasiclassical Keldysh theory, the Green function matrix g<cb><2021> is used to compute a variety of physical quantities in mesoscopic systems. However, solving the set of non-linear differential equations that provide g<cb><2021> becomes a challenging task when going to higher spatial dimensions than one. Such an extension is crucial in order to describe physical phenomena like charge/spin Hall effects and topological excitations like vortices and skyrmions, none of which can be captured in one-dimensional models. We here present a numerical finite element method which solves the 2D and 3D quasiclassical Usadel equation, without any linearisation, relevant for the diffusive regime. We show the application of this on two model systems with non-trivial geometries: (i) a bottlenecked Josephson junction with external flux and (ii) a nanodisk ferromagnet deposited on top of a superconductor. We demonstrate that it is possible to control externally not only the geometrical array in which superconducting vortices arrange themselves, but also to cause coalescence and thus tune the number of vortices. The finite element method presented herein could pave the way for gaining insight in physical phenomena which so far have remained largely unexplored due to the complexity of solving the full quasiclassical equations in higher dimensions.  
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  Notes Approved no  
  Call Number Serial 1066  
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Author Shurakov, A.; Tong, Cheuk-yu E.; Grimes, P.; Blundell, R.; Golt'sman, G. openurl 
  Title A microwave reflection readout scheme for hot electron bolometric direct detector Type Journal Article
  Year 2015 Publication IEEE Trans. THz Sci. Technol. Abbreviated Journal IEEE Trans. THz Sci. Technol.  
  Volume 5 Issue Pages 81-84  
  Keywords HEB detectors  
  Abstract (up) In this paper, we propose and present data from a fast THz detector based on the repurpose of hot electron bolometer mixers (HEB) fabricated from superconducting NbN thinfilm. This detector is essentially a traditional NbN bolometer element that operates under the influence of a microwave pump. The in-jected microwave power serves the dual purpose of enhancing the detector sensitivity and reading out the impedance changes of the device in response to incidentTHz radiation. We have measured an optical Noise Equivalent Power of 4 pW/ Hz for our detector at a bath temperature of 4.2 K. The measurement frequency was 0.83 THz and the modulation frequency was 1.48 kHz. The readout

scheme is versatile and facilitates both high-speed operation as well as multi-pixel applications.
 
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  Notes Approved no  
  Call Number RPLAB @ atomics90 @ Serial 950  
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Author Fedorov, G. E.; Gaiduchenko, I. A.; Golikov, A. D.; Rybin, M. G.; Obraztsova, E. D.; Voronov, B. M.; Coquillat, D.; Diakonova, N.; Knap, W.; Goltsman, G. N.; Samartsev, V. V.; Vinogradov, E. A.; Naumov, A. V.; Karimullin, K. R. url  doi
openurl 
  Title Response of graphene based gated nanodevices exposed to THz radiation Type Conference Article
  Year 2015 Publication EPJ Web of Conferences Abbreviated Journal EPJ Web of Conferences  
  Volume 103 Issue Pages 10003 (1 to 2)  
  Keywords graphene field-effect transistor, FET  
  Abstract (up) In this work we report on the response of asymmetric graphene based devices to subterahertz and terahertz radiation. Our devices are made in a configuration of a field-effect transistor with conduction channel between the source and drain electrodes formed with a CVD-grown graphene. The radiation is coupled through a spiral antenna to source and top gate electrodes. Room temperature responsivity of our devices is close to the values that are attractive for commercial applications. Further optimization of the device configuration may result in appearance of novel terahertz radiation detectors.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2100-014X ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1350  
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Author Anosov, A. A.; Nemchenko, O. Yu.; Less, Yu. A.; Kazanskii, A. S.; Mansfel'd, A. D. doi  openurl
  Title Possibilities of acoustic thermometry for controlling targeted drug delivery Type Journal Article
  Year 2015 Publication Acoust. Phys. Abbreviated Journal  
  Volume 61 Issue 4 Pages 488-493  
  Keywords acoustic thermometry, liposome suspension, thermography  
  Abstract (up) Model acoustic thermometry experiments were conducted during heating of an aqueous liposome suspension. Heating was done to achieve the liposome phase transition temperature. At the moment of the phase transition, the thermal acoustic signal achieved a maximum and decreased, despite continued heating. During subsequent cooling of the suspension, when lipids again passed through the phase transition point, the thermal acoustic signal again increased, despite a reduction in temperature. This effect is related to an increase in ultrasound absorption by the liposome suspension at the moment of the lipid phase transition. The result shows that acoustic thermography can be used to control targeted delivery of drugs mixed in thermally sensitive liposomes, the integrity of which is violated during heating to the phase transition temperature.  
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  Notes Approved no  
  Call Number Serial 1130  
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Author Elezov, M. S.; Ozhegov, R. V.; Kurochkin, Y. V.; Goltsman, G. N.; Makarov, V. S.; Samartsev, V. V.; Vinogradov, E. A.; Naumov, A. V.; Karimullin, K. R. url  doi
openurl 
  Title Countermeasures against blinding attack on superconducting nanowire detectors for QKD Type Conference Article
  Year 2015 Publication EPJ Web Conf. Abbreviated Journal EPJ Web Conf.  
  Volume 103 Issue Pages 10002 (1 to 2)  
  Keywords SSPD, SNSPD, QKD  
  Abstract (up) Nowadays, the superconducting single-photon detectors (SSPDs) are used in Quantum Key Distribution (QKD) instead of single-photon avalanche photodiodes. Recently bright-light control of the SSPD has been demonstrated. This attack employed a “backdoor” in the detector biasing technique. We developed the autoreset system which returns the SSPD to superconducting state when it is latched. We investigate latched state of the SSPD and define limit conditions for effective blinding attack. Peculiarity of the blinding attack is a long nonsingle photon response of the SSPD. It is much longer than usual single photon response. Besides, we need follow up response duration of the SSPD. These countermeasures allow us to prevent blind attack on SSPDs for Quantum Key Distribution.  
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  ISSN 2100-014X ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1352  
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Author Takesue, Hiroki; Dyer, Shellee D.; Stevens, Martin J.; Verma, Varun; Mirin, Richard P.; Nam, Sae Woo doi  openurl
  Title Quantum teleportation over 100 km of fiber using highly efficient superconducting nanowire single-photon detectors Type Journal Article
  Year 2015 Publication Abbreviated Journal Optica  
  Volume 2 Issue Pages  
  Keywords  
  Abstract (up) Quantum teleportation is an essential quantum operation by which we can transfer an unknown quantum state to a remote location with the help of quantum entanglement and classical communication. Since the first experimental demonstrations using photonic qubits and continuous variables, the distance of photonic quantum teleportation over free-space channels has continued to increase and has reached >100 km. On the other hand, quantum teleportation over optical fiber has been challenging, mainly because the multifold photon detection that inevitably accompanies quantum teleportation experi- ments has been very inefficient due to the relatively low de- tection efficiencies of typical telecom-band single-photon detectors. Here, we report on quantum teleportation over optical fiber using four high-detection-efficiency supercon- ducting nanowire single-photon detectors (SNSPDs). These SNSPDs make it possible to perform highly efficient multi- fold photon measurements, allowing us to confirm that the quantum states of input photons were successfully tele- ported over 100 km of fiber with an average fidelity of 83.7  2.0%.  
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  Notes Approved no  
  Call Number RPLAB @ alex_kazakov @ Serial 1004  
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Author Maezawa, Hiroyuki openurl 
  Title Application of superconducting hot-electron bolometer mixers for terahertz-band astronomy Type Journal Article
  Year 2015 Publication IEICE Trans. Electronics Abbreviated Journal  
  Volume 98 Issue 3 Pages 196-206  
  Keywords HEB mixer applications, HEB applications  
  Abstract (up) Recently, a next-generation heterodyne mixer detector – a hot electron bolometer (HEB) mixer employing a superconducting microbridge – has gradually opened up terahertz-band astronomy. The surrounding state-of-the-art technologies including fabrication processes, 4 K cryostats, cryogenic low-noise amplifiers, local oscillator sources, micromachining techniques, and spectrometers, as well as the HEB mixers, have played a valuable role in the development of super-low-noise heterodyne spectroscopy systems for the terahertz band. The current developmental status of terahertz-band HEB mixer receivers and their applications for spectroscopy and astronomy with ground-based, airborne, and satellite telescopes are presented.  
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  Notes Approved no  
  Call Number Serial 1073  
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Author Kahl, O.; Ferrari, S.; Kovalyuk, V.; Goltsman, G. N.; Korneev, A.; Pernice, W. H. P. doi  openurl
  Title Waveguide integrated superconducting single-photon detectors with high internal quantum efficiency at telecom wavelengths Type Journal Article
  Year 2015 Publication Sci. Rep. Abbreviated Journal Sci. Rep.  
  Volume 5 Issue Pages 10941 (1 to 11)  
  Keywords optical waveguides; waveguide integrated SSPD; waveguide SSPD; nanophotonics  
  Abstract (up) Superconducting nanowire single-photon detectors (SNSPDs) provide high efficiency for detecting individual photons while keeping dark counts and timing jitter minimal. Besides superior detection performance over a broad optical bandwidth, compatibility with an integrated optical platform is a crucial requirement for applications in emerging quantum photonic technologies. Here we present efficiencies close to unity at 1550nm wavelength. This allows for the SNSPDs to be operated at bias currents far below the critical current where unwanted dark count events reach milli-Hz levels while on-chip detection efficiencies above 70% are maintained. The measured dark count rates correspond to noiseequivalent powers in the 10–19W/Hz–1/2 range and the timing jitter is as low as 35ps. Our detectors are fully scalable and interface directly with waveguide-based optical platforms.  
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  Notes PMID:26061283; PMCID:PMC4462017 Approved no  
  Call Number RPLAB @ kovalyuk @ Serial 946  
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Author Mehdi, I.; Gol'tsman, G.; Putz, P. url  doi
openurl 
  Title Introduction to the mini-special-issue on the 25th international symposium on space terahertz technology (ISSTT) Type Miscellaneous
  Year 2015 Publication IEEE Trans. THz Sci. Technol. Abbreviated Journal IEEE Trans. THz Sci. Technol.  
  Volume 5 Issue 1 Pages 14-15  
  Keywords  
  Abstract (up) THE 25th International Symposium on Space Terahertz Technology (ISSTT) was held in Moscow, Russia, between April 27–30, 2014. The conference was organized by Moscow State Pedagogical University and the Higher School of Economics (National Research University) and Chaired by Professor Gregory Gol'tsman of Moscow State Pedagogical University. The conference was attended by roughly 150 participants from 15 countries. The technology covered by ISSTT includes detectors, devices, circuits and systems in various areas of THz science and technology. Each year this symposium brings together the global THz space science technology community, and as such, emphasizes the broad international collaboration that is required to execute these large complicated instrument programs that dominate this field. However, talks covering technologies for balloon, aircraft, and ground-based telescopes were also presented.

In this special section of IEEE Transactions on Terahertz Science and Technology, we include eight expanded papers from the 25th ISSTT symposium. The papers range from development of SIS mixers to optical adjustment systems for radio telescopes. The 26th ISSTT will be held in Boston, MA, USA, during March 16–18, 2015. Researchers and scientist involved in THz research are invited to attend this symposium (more details are at http://www.cfa.harvard.edu/events/2015/isstt2015/).

You can access the full list of papers presented at the ISSTT symposia from the National Radio Astronomy Observatory website: http://www.nrao.edu/meetings/isstt/index.shtml

Yours sincerely
 
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2156-342X ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1353  
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Author Shurakov, A.; Lobanov, Y.; Goltsman, G. url  doi
openurl 
  Title Superconducting hot-electron bolometer: from the discovery of hot-electron phenomena to practical applications Type Journal Article
  Year 2015 Publication Supercond. Sci. Technol. Abbreviated Journal Supercond. Sci. Technol.  
  Volume 29 Issue 2 Pages 023001  
  Keywords HEB  
  Abstract (up) The discovery of hot-electron phenomena in a thin superconducting film in the last century was followed by numerous experimental studies of its appearance in different materials aiming for a better understanding of the phenomena and consequent implementation of terahertz detection systems for practical applications. In contrast to the competitors such as superconductor-insulator-superconductor tunnel junctions and Schottky diodes, the hot electron bolometer (HEB) did not demonstrate any frequency limitation of the detection mechanism. The latter, in conjunction with a decent performance, rapidly made the HEB mixer the most attractive candidate for heterodyne observations at frequencies above 1 THz. The successful operation of practical instruments (the Heinrich Hertz Telescope, the Receiver Lab Telescope, APEX, SOFIA, Hershel) ensures the importance of the HEB technology despite the lack of rigorous theoretical routine for predicting the performance. In this review, we provide a summary of experimental and theoretical studies devoted to understanding the HEB physics, and an overview of various fabrication routes and materials.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0953-2048 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1156  
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