Microwave Experiments and Noise in Mesoscopic Devices

Jayanta Sarkar

Research output: ThesisDoctoral ThesisCollection of Articles

Abstract

This thesis is a compilation of several works in the area of condensed matter physics, and with devices based on superconducting Josephson junctions (JJ) as the common denominator for the presented projects apart from the work on diffusive systems. Microwave measurements were conducted on a Superconducting Cooper pair transistor to explore its current-phase relationship. Measurements on a JJ-based qubit coupled to a LC resonator revealed the vibronic transitions obeying the Franck-Condon principle. The main body of the thesis is the work done on the Bloch Oscillating Transistor (BOT), an ultra low noise quantum amplifier. In the present work, we investigated the dynamics of the BOT near the bifurcation threshold as well as implemented differential BOTs to check its capability to reject common mode signals. To account for our studies of quantum features in mesoscopic systems other than JJs, we performed an experiment similar to the Hanbury-Brown and Twiss interferometry in optics. For this mesoscopic interference experiment we selected a multiterminal diffusive system. We developed a low temperature noise measurement scheme to study current-current correlations in the GHz frequency range. In our experiments we found a small positive HBT exchange correction factor in the non-interacting limit at low bias voltage in the presence of quantum interference. We found negative exchange correction factor in the hot electron case for similar structures, which agrees well with the theory. Altogether, our experiments demonstrated the theoretically predicted HBT exchange effects in non-interacting and interacting regime of electron transport in a diffusive mesoscopic system.
Translated title of the contributionMicrowave Experiments and Noise in Mesoscopic Devices
Original languageEnglish
QualificationDoctor's degree
Awarding Institution
  • Aalto University
Supervisors/Advisors
  • Hakonen, Pertti, Supervising Professor
  • Hakonen, Pertti, Thesis Advisor
Publisher
Print ISBNs978-952-60-6207-5
Electronic ISBNs978-952-60-6208-2
Publication statusPublished - 2015
MoE publication typeG5 Doctoral dissertation (article)

Keywords

  • low temperature
  • bloch oscillating transistor
  • Superconducting Cooper pair transistor
  • artificial atom
  • diffusive system
  • shot noise
  • current-current correlation

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