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장소 Zoom Video 
일시 Sep. 24(Thu), 09:00~, Sep. 24(Thu), 16:00 ~ 
연사 Akash V. Dixit (University of Chicago), Dr. Boris Ivanov (Novosibirsk State Technical University) 

Speaker: Akash V. Dixit (University of Chicago)


Date: September 24, 2020 (Thursday)


Time: 9:00 AM


Venue: Zoom Video Conference System (Please click the link below)

Meeting ID: 610 806 8959

Passcode: 131015


Topic: Searching for Dark Matter with a Superconducting Qubit


The gravitational evidence for the existence of dark matter is extensive 1 , yet thus far, dark matter has evaded direct detection in terrestrial experiments. Detection mechanisms for low mass dark matter candidates such as the axion 2–5 or hidden photon 6,7 leverage potential interactions with electromagnetic fields, whereby the dark matter (of unknown mass) on rare occasion converts into a single photon 8,7. Current dark matter searches operating at microwave frequencies, use a resonant cavity to coherently accumulate the field sourced by the dark matter and use a quantum limited linear amplifier to read out the cavity signal 9–12. Here, we report the development of a novel microwave photon counting technique and use it to set a new exclusion limit on hidden photon dark matter. We constrain the kinetic mixing angle to  ≤ 1.82 × 10−15 in a narrow band around 6.011 GHz (24.86 µeV) with an integration time of 8.33 s. We operate a superconducting qubit to make repeated quantum non-demolition measurements of cavity photons and apply a hidden Markov model analysis to reduce the noise to 15.7 dB below the quantum limit, with performance limited by the residual population of the system. The techniques presented here will dramatically improve the sensitivity of future dark matter searches in the range of 3-30 GHz and are generally applicable to measurements that require high sensitivity to inherently low signal photon rates.


Seminar Invitation (September 24, 2020), 4 PM

Speaker: Dr. Boris Ivanov (Novosibirsk State Technical University)

Date: September 24, 2020 (Thursday)

Time: 4:00 PM

Venue: Webinar Video Conference System (Please click the link below)

Seminar Name: Cryogenic Microwave Circuit Development at the NSTU

Password: None


Topic: Cryogenic Microwave Circuit Development at the NSTU


During the seminar I am going to show the last scientific results of 4 research performed in the Laboratory of Quantum and Cryogenic Electronics. I will concentrate the major part of the talk around cryogenic amplifiers design, development and characterization. Thus, the cryogenic low noise amplifier with the noise temperature of 6 K and gain value of more than 30 dB is shown for the frequency range from 6 to 12 GHz. Based on such microwave amplifiers the superconducting X-mon qubit structures were measured. The experiments with qubits were performed at continues microwave field and with short microwave pulses. The qubit energy spectrums were obtained and based on the AC-Stark experiment the low average photon number close to single photon mode in qubit-resonator structure was obtained. From the other side for the bolometer circuits readout and Josephson junctions measurements the low frequency cryogenic amplifiers were designed and characterized. The minimum voltage noise density corresponds to 150 pV/root(Hz) with the gain value of more than 60 dB for the presented amplifiers.

번호 일시 장소 연사 제목
공지 2019/09/18 - 12/5  Seminar Room #1323  Prof. David Schuster and etc.  Fall 2019: Physics Seminar Serises
공지 2019/09/02 - 12/09  Seminar Room 1501  이호성 박사 (한국표준과학연구원) and etc.  Fall 2019: Physics Colloquium
45 October 15 (Tue.), 16:00 PM  #1323, E6-2  Prof. Pilkyung Moon  Moiré superlattices and graphene quasicrystal file
44 October 15, 2020 (Thursday  CAPP Seminar Room #C303, Creation Hall (3F), KAIST Munji Campus  Prof. Gil-Ho Lee (POSTECH)  Graphene-based Josephson junction microwave bolometer file
43 October 15, 5:00pm  Dr. Samuli Autti  Time crystals, quasicrystals, and time crystal dynamics in the superfluid universe file
42 October 16 (Tue.), 10:00 AM  #1323, E6-2  Dr. Won-Ki Cho  Capturing protein cluster dynamics and gene expression output in live cells file
41 October 16 (Wed), 4:00pm  #1323 (E6-2, 1st fl.)  Dr. Jaewon Song  Emergent black holes and monopoles from quantum fields file
40 October 17 (Thu.), 16:00 PM  #1323, E6-2  Prof. Namkyoo Park  Top down manipulation of Waves : From Metamaterials, Correlated Disorder, Quantum Analogy, to Digital Processing file
39 October 18 (Thu.), 10:00 AM  #1323, E6-2  Dr. Duyoung Min  Understanding membrane protein folding using single-molecule force techniques file
38 October 18 (Thu.), 16:00 PM  #1323, E6-2  Prof. Jongseok Lee  Applications of nonlinear optics for condensed matter researches file
37 October 19 (Fri.), 10:00 AM  #1323, E6-2  Dr. Jongsoo Yoo  Energy conversion processes during magnetic reconnection in a laboratory plasma file
36 October 24 (Wed.), 10:30 AM  E6-1, Lecture Room 1501(1F)  Prof. Kerry J. Vahala  Photonic integration of next-generation clocks and Hertz-absolute-accuarcy optical frequenncy synthesizers file
35 October 25 (Thu.), 4:00 PM  #1323, E6-2  Dr. Gang Li  Abelian and non-Abelian dark photons file
34 October 26 (Fri.), 4:00 PM  #1323, E6-2  Dr. Kyusung Hwang  Coexisting triple-point and nodal-line topological magnons and thermal Hall effect in pyrochlore iridates file
33 October 29 (Tue.), 10:00am  #1323 (E6-2, 1st fl.)  Prof. Se Kwon Kim  Unconventional Spin Transport in Quantum Materials file
32 October 29 (Tue.), 14:30 PM  #1323, E6-2  Prof. Jörg Wrachtrup  Quantum sensing file
31 October 29 (Tue.), 4:00pm  #1323 (E6-2, 1st fl.)  Dr. Seung-Joo Lee  Particles and Gravity via String Geometry file
30 October 31 (Thu.), 10:00am  #1323 (E6-2, 1st fl.)  Dr. Seung-Sup Lee  Kondo meets Hubbard: Impurity physics for correlated lattices file
29 October 4 (Thu.), 16:00 PM  #1323, E6-2  Prof. Soo Jin Kim  Engineering light absorption in an ultrathin semiconductor metafilm file
28 Sep. 02(Fri) 2:30 PM  E6-2(1st fl.), #1323  Dr. Yong-Hyun Kim,Graduate School of Nanoscience and Technology, KAIST  Nanoscale Thermal Physics: Seebeck Effect and Nanoscale Friction
27 Sep. 02(Fri) 4:00 PM  E6-2(1st fl) #1323  Dr. Yong-Joo Doh, Department of Physics and Photon Science, GIST  Quantum Electrical Transport in Topological Insulator Nanowires
26 Sep. 10 (Tue.), 03:00 PM  E6-2. 1st fl. #1323  Dr. Mikhail Kiselev  Two-Stage Kondo Effect file