 
Summary: Universal Impedance Fluctuations in Wave Chaotic Systems
Sameer Hemmady,* Xing Zheng,
Edward Ott,*,
Thomas M. Antonsen,*,
and Steven M. Anlage*,
Physics Department, University of Maryland, College Park, Maryland 207424111, USA
(Received 26 December 2003; revised manuscript received 7 May 2004; published 6 January 2005)
We experimentally investigate theoretical predictions of universal impedance fluctuations in wave
chaotic systems using a microwave analog of a quantum chaotic infinite square well potential. We
emphasize the use of the radiation impedance to remove the nonuniversal effects of the particular
coupling between the outside world and the scatterer. Specific predictions that we test include the
probability density functions (PDFs) of the real and imaginary parts of the universal impedance, the
equality of the variances of these PDFs, and the dependence of these PDFs on a single loss parameter.
DOI: 10.1103/PhysRevLett.94.014102 PACS numbers: 05.45.Mt, 05.45.Gg, 41.20.Jb, 84.40.Az
There is interest in the small wavelength behavior of
quantum (wave) systems whose classical (ray orbit) limit is
chaotic. Despite their apparent complexity, quantum cha
otic systems have remarkable universal properties. Much
prior work has focused on identifying the universal statis
tical properties of wave chaotic systems such as quantum
