Leiden University
Colloquium Ehrenfestii 2017


COLLOQUIUM EHRENFESTII 2017

initiated by Paul Ehrenfest in 1912
currently organized by Vincenzo Vitelli & Koenraad Schalm (read about its history)


Meal reservation form

10 May

Michael Berry (Bristol)

Variations on a theme of Aharonov and Bohm

The Aharonov-Bohm effect (AB) concerns the role in quantum physics of the magnetic vector potential of an impenetrable line of magnetic flux. Its partial anticipation by Ehrenberg and Siday, in terms of interference, was an approximation whose wavefunction was not singlevalued. Its connection with the singlevalued AB wave involves topology: ‘whirling waves’ winding round the flux. AB is a fine illustration of idealization in physics. There are four AB effects, depending on whether the waves and the flux are classical or quantum. In the classical-classical case, many details of the AB wavefunction have been explored experimentally in ripples scattered by a water vortex, where the flow velocity of the water corresponds to the vector potential; this analogy has recently been extended to include superradiance. The AB wave possesses a phase singularity, and there is a similar phenomenon in general interferometers. Connections between the AB wave and the Cornu spiral describing edge diffraction lead to very accurate approximations.


The Colloquium Ehrenfestii takes place Wednesday evenings starting at 19:30 hours in the main auditorium of the Oort building. Before the Colloquium, there is a common dinner in the canteen located on the ground floor of the Oort building. This dinner starts at 18:00 hours sharp and is free of charge, under the condition that one attends the colloquium and that one has made a reservation before noon on the Tuesday preceding the colloquium. [Registration may close earlier, when 80 persons have signed up]

Colloquium Ehrenfestii 2017

1 Feb

Leo Radzihovsky (Boulder)

Chiral symmetry breaking, emergent Higgs mechanism, and critical matter

15 Feb

Yossi Avron (Technion)

The geometry of non-dissipative transport: From conductance to viscosity

1 Mar

Oleg Lavrentovich (Kent State)

Dynamics of colloids in liquid crystals

8 Mar

Anne Davis (Cambridge)

The accelerating Universe

5 Apr

Jacques Prost (Curie Institute)

Long-time tissue dynamics and multicellular spheroids

19 Apr

Cristina Marchetti (Syracuse)

Active Matter: from colloids to living cells

10 May

Michael Berry (Bristol)

Variations on a theme of Aharonov and Bohm

31 May

Julia Yeomans (Oxford)

TBA

14 Jun

Renata Kallosh (Lorentz Professor)

TBA

Programs from previous years

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