Universal Conductance Fluctuations in a Ballistic Quantum Dot. The fluctuations are random, but symmetric in B. By changing the center gate, Vg, an ensemble of dot shapes can be generated, as shown below. From C. M. Marcus, et al "Quantum Chaos in Open versus Closed Quantum Dots: Signatures of Interacting Particles" In: Chaos, Solitons and Fractals 8, 1261 (1997).
Landscape of conductance fluctuations (low conductance is dark, high conductance is light) as a function of magnetic field (horizontal) and shape distortion (vertical). Note the entire pattern retains its symmetry about zero magnetic field.
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