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VERSION:2.0
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METHOD:PUBLISH
BEGIN:VEVENT
DTSTAMP:20260729T020618Z
LAST-MODIFIED:20121116T203436Z
DTSTART:20071102T150000Z
DTEND:20071102T160000Z
UID:event152@bu.edu
URL:http://physics.bu.edu/internal/events/show/152
SUMMARY:"Quantum Coherence in Networks"
DESCRIPTION:Featuring Laurent Saminadayar\, CNRS\, Grenoble\nHosted by: Raj
	 Mohanty\n\nPart of the Biophysics/Condensed Matter Seminar Series.\n\nAbst
	ract:  Magnetoconductance oscillations in mesoscopic rings are the most str
	iking evidence of the quantum nature of the transport in mesocopic devices.
	 These oscillation may be either 0=h/e periodic for single rings (Aharon
	ov-Bohm oscillations) or 0/2 periodic for large networks (Altshuler-Aron
	ov-Spivak oscillations). The problem of the transition between these two ex
	treme situations have been explored by considering lines of silver rings of
	 different lengths: in this case\, simple arguments show that the AB oscill
	ations decease as N-1/2\, whereas the AAS oscillations are constant with N\
	, N being the number of rings.\nIn this talk\, we will show that this so-ca
	lled ensemble averaging indeed depends on the dimensionality of the system:
	 from measurements of both AB and AAS oscillations in 2D networks\, we will
	 show that\, when the phase coherence length of the electrons becomes of th
	e order of the width of the network\, the diffusive motion of the electrons
	 is actually one-dimensional although the network is 2D. One thus observes 
	a 1D2D cross-over in the dependence of the amplitude of magnetoconductan
	ce oscillations as a function of the number of plaquettes of the network. T
	his cross-over from mesoscopic to macroscopic behavior in the ensemble aver
	aging shows that the usual addition of coherent blocs in mesoscopic physics
	 is indeed very subtle.\n\n[1]F. Schopfer\, F. Mallet\, D. Mailly\, G. Mont
	ambaux\, C. Texier\, C. Bäuerle and L. Saminadayar\,\nPhys. Rev. Lett. 98\
	, 026807 (2007)\n[2]F. Mallet\, Y. Niimi\, F. Schopfer\, Y. Baines\, D. Mai
	lly\, C. Texier\,G. Montambaux\, C. Bäuerle and L~Saminadayar\, submitted 
	to Phys. Rev. Lett. (2007)
LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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