[Theory-seminars] Fwd: Please Save The Date: Special Physics & Applied Science Colloquium Friday, July 31, 2015 "Optical Spectroscopy on Superconducting Films" - Dr. Martin Dressel

[Mary Fox]

-------- Original Message --------
Subject: 	Please Save The Date: Special Physics & Applied Science 
Colloquium Friday, July 31, 2015 "Optical Spectroscopy on 
Superconducting Films" - Dr. Martin Dressel
Date: 	Wed, 24 Jun 2015 20:07:13 +0000
From: 	Wilkinson, Eleonor V <evwilk at wm.edu>
To: 	'physics0607 at physics.wm.edu' <physics0607 at physics.wm.edu>
CC: 	'undergrads0607 at physics.wm.edu' <undergrads0607 at physics.wm.edu>



*_PHYSICS & APPLIED SCIENCE COLLOQUIUM_*

Friday, July 31, 2015

4:00 PM

Small Hall, Room 111

*Dr. Martin Dressel *[Hosts: M. Qazilbash & G. Luepke]

1. Physikalisches Institut, Universität Stuttgart, Germany

*Title of Talk:*

/Optical Spectroscopy on Superconducting Films/

**

*Abstract:*

The electrodynamic properties of superconductors are of interest from a 
fundamental side as well as for applications.  Since the seminal work of 
M. Tinkham on the superconducting energy gap in the late 1950s optical 
investigations have been established as a powerful method to explore the 
quasi-particle excitations and their dynamics which yield important 
information on the density of states, the symmetry of the order 
parameter, the scattering mechanism, and eventually the glue to 
super¬conductivity. In addition, the superconducting condensate is 
probed, i.e. the Cooper pair density and stiffness. Most recently, it 
became clear that under certain conditions, also collective modes can be 
studied: these are the phason excitations (Nambu-Goldstone mode) and the 
amplitude mode (Higgs mode).

The talk will give a general introduction to the optical properties of 
superconductors, sketch the theory and highlight some important 
experimental findings, as well as applications, such as superconducting 
single photon detectors. In particular we will focus on ultrathin 
superconducting films, such as InO, Nb, NbN, TiN, and TaN, but also Al, 
which exhibit a superconductor-insulator transition as disorder or 
granularity increases. We discuss the possibility of collective 
low-frequency ex¬citations due to the Higgs mechanism, which become 
long-lived and well defined in the vicinity of a quantum critical point.

References

[1] M. Dressel et al., IEEE Sel. Top. Quant. Electr. 14, 399 (2008); 
Adv. Condens. Matter Phys. 2013, 104379 (2013).

[2] U. S. Pracht et al., IEEE Trans. THz Sci. Technol. 3, 269 (2013); 
Phys. Rev. B 86, 184503 (2012).

[3] D. Sherman et al., Phys. Rev. B 89, 035149 (2014); Nature Phys. 11, 
188 (2015).

[4] N. Bachar et al., J. Low Temp. Phys. 179, 83 (2014).*//*

*//*

*//*

*/*Refreshments will be served in Room 122 at 3:30 PM/*

  ******

*Eleonor V. Wilkinson*

Administrative & Office Specialist

The College of William & Mary-Physics
Small Hall, Room 123
300 Ukrop Way
Williamsburg, VA 23185

Telephone: 757-221-3503

Fax: 757-221-3540



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