Danny Schumayer

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Danny Schumayer (2011)

Dr Daniel Schumayer

MSc, PhD (BMGE, Budapest, Hungary)

Research Fellow

  • Room: 522
  • Phone: 479 7815
  • Email: <mail>daniel.schumayer@otago.ac.nz</mail>

Research Interests

Currently I am interested in developing algorithms and applying inference techniques to industrial problems. As data acquisition and storage becomes more and more available, a need emerges for increasingly sophisticated data analysis.

  • Models of crystal oscillators: most of our everyday electronic devices (e.g. mobile, laptops, tablets, GPS, etc) have to keep track of time, measure geographic location or distance travelled. In order to achieve any of these tasks clocks, preferable precise clocks, are needed, and crystal oscillators provide a solution for achieving this aim. However, there are many factors which limit the precision of such oscillators. Our aim is to improve our understanding of the physics of these oscillators, and develop algorithms which may help in artificially eliminating some of these limiting factors in real applications.
  • Inference algorithms for continuous measurements: As computational power rapidly increasing, variety of the practically useful statistical algorithms can be directly adapted and utilised for industrial problems. In our group we attempt to implement such algorithms in already existing commercial devices, thereby improving their performance without the need of possibly costly re-design of the hardware.
  • Precision agriculture and decision support systems: New Zealand's economy hugely rely on the performance of its agriculture sector, therefore any improvement in the analysis of measurements (e.g. weight gain of an animal) or any improvement in predicting the likelihood of events based on measurements may have substantial outcome not only for the individual farmers, but eventually for the country as well. In the electronics group, we engage in developing not only the devices for precise measurements, but also (statistical) algorithms which do not necessarily demand large-scale post-processing.

Selection of recent projects

As a Research Fellow at the University of Otago I have been involved mainly in theoretical research projects employing both analytical and numerical skills. Some recent projects are:

  • Together with Samuel C. Cormack and David Hutchinson, we developed a Path-Integral Monte-Carlo simulation to explain the relationship between the shift in the critical temperature in a boson gas due to interaction and the roton minimum emerging in the excitation spectrum (accepted in Phys. Rev. Lett.).
  • With colleagues from my alma mater, we examined whether quantum chaos can be interpreted in the classical limit for a one-dimensional system (Phys. Rev. E., 84(1), 016230 (2011)).
  • The previous project, namely constructing a quantum mechanical potential with energy spectrum coinciding with the prime numbers, appears to be a rather artificial model, however it may provide an important insight to the distribution of the prime numbers, which is at the heart of the Riemann hypothesis. We have reviewed the most important physical models from the last five decades which attempted to tackle this hypothesis (Rev. Mod. Phys., 83(2) 307-330 (2011)).
  • We examine the effect of the intra- and interspecies scattering lengths on the dynamics of a two-component Bose-Einstein condensate, particularly focusing on the existence and stability of solitonic excitations (Phys. Rev. A., 82(6), 063608 (2010)).
  • In collaboration with R. Bhaduri (Canada) and B. van Zyl (Canada) we predicted an Efimov-like effect in the spectrum of an electron captured by a finite dipole (Europhysics Letters, 89, 13001 (2010), selected into the "Best articles of EPL in 2010" list).
  • Later, with E. Zaremba (Canada) and B. van Zyl, we extended the semi-classical description of Bose-Einstein condensation around the critical temperature (under publication).
  • Using Inverse Scattering Transformation technique, we have connected number theory and one-dimensional quantum physics, providing a fractal potential which reproduces the prime numbers as energy eigenvalues (Phys. Rev. E., 78(5), 056215 (2008)).


Teaching:

  • PHSI451 — Statistical and Condensed Matter Physics
  • ELEC443 — Boundary value problems of mathematical physics
  • ELEC442 — Digital signal processing
  • ELEC422 — Upper Atmospheric and Space Physics
  • PHSI366 — Condensed Matter Physics (only superconductivity)
  • PHSI365 — Computational Physics
  • ELEC358 — Electronic Design Techniques
  • ELEC353 — Analog electronics
  • PHSI231 — Quantum and Thermal Physics
  • PHSI191 — Biological Physics
  • Jumpstart Physics