Szemináriumok

The Surface Code

Időpont: 
2017. 12. 08. 14:15
Hely: 
Building F, Entrance I, 1st Floor, Department of Physics, Room 5 (seminar) room.
Előadó: 
János Asbóth (Wigner RC)
A szeminárium részletei: 
http://physics.bme.hu/node/3909

Title: "The Surface Code -- how to realize topological quantum computing in the lab"

Structured light and the spatial shaping of fields and atoms

Időpont: 
2017. 12. 11. 14:15
Hely: 
Building F, Entrance III, seminar room of Department of Theoretical Physics
Előadó: 
Thomas W. Clark (Wigner RC)
A szeminárium részletei: 
http://physics.bme.hu/node/3908

Title:

"Sculpting Shadows - Structured light and the spatial shaping of fields and atoms"

Abstract:

Twenty-five years ago this year, Allen, Beijersbergen, Spreeuw, and Woerdman reported that light carries two types of angular momentum: spin (polarization) and orbital angular momentum. Although it had been known for some time that light could exert a momentum of hbar, it was only after the work of Allen et al. that it was understood that the systematic winding of wavefronts could lead to an unbounded source of angular momentum: an inifinite-dimensional phase-space that came with a twist. Such a discovery has had a vast influence across the field of optics, extending through mechanical manipulation, imaging, communications and the quantum realm. In this seminar, I selectively review the creation and manipulation of spatially-structured light, before detailing how this can be applied to interaction with atomic systems. Throughout, I will focus on work undertaken at Glasgow, concluding with recent results on how phase-shaped light can be used to sculpt the refractive index and populations of an atomic cloud.

Electron g-factor in semiconductor nanowires

Időpont: 
2017. 12. 18. 14:15
Hely: 
Building F, Entrance III, seminar room of Department of Theoretical Physics
Előadó: 
Dániel Varjas (Delft)
A szeminárium részletei: 
http://physics.bme.hu/seminar_eqp?language=en

Title: "Orbital contributions to the electron g-factor in semiconductor nanowires"

Abstract: "Recent experiments on Majorana fermions in semiconductor nanowires revealed a surprisingly large electronic Lande g-factor, several times larger than the bulk value - contrary to the expectation that confinement reduces the g-factor. Here we assess the role of orbital contributions to the electron g-factor in nanowires and quantum dots. We show that an LS coupling in higher subbands leads to an enhancement of the g-factor of an order of magnitude or more for small effective mass semiconductors. We validate our theoretical finding with simulations of InAs and InSb, showing that the effect persists even if cylindrical symmetry is broken. A huge anisotropy of the enhanced g-factors under magnetic field rotation allows for a straightforward experimental test of this theory."

 

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