Is it the boundaries or disorder that dominates electron transport in semiconductor `billiards'?

Semiconductor billiards are often considered as ideal systems for studying dynamical chaos in the quantum mechanical limit. In the traditional picture, once the electron's mean free path, as determined by the mobility, becomes larger than the device, disorder is negligible and electron trajectories are shaped by specular reflection from the billiard walls alone. Experimental insight into the electron dynamics is normally obtained by magnetoconductance measurements. A number of recent experimental studies have shown these measurements to be largely independent of the billiards exact shape, and highly dependent on sample-to-sample variations in disorder. In this paper, we discuss these more recent findings within the full historical context of work on semiconductor billiards, and offer strong evidence that small-angle scattering at the sub-100 nm length-scale dominates transport in these devices, with important implications for the role these devices can play for experimental tests of ideas in quantum chaos.Comment: Submitted to Fortschritte der Physik for special issue on Quantum Physics with Non-Hermitian Operator

Improving the Culture of Ethical Behavior in the Financial Sector: Time to Expressly Provide for Private Enforcement Against Aiders and Abettors of Securities Fraud

Financial markets do not function well when fraud is pervasive. It has been well documented that financial fraud has increased following changes in securities law that occurred in the 1990\u27s. Also around September of 2009, the investigations into the SEC examinations of Bernard Madoff Investment Securities, LLC were completed and released to the public. The simple facts reveal an alarming level of incompetence and lack offinancial literacy on the part of the guardians of the integrity of our financial markets. I suggest two important tools for addressing these problems. One is to supplement enforcement of anti-fraud rules with more private attorney generals by expressly creating a private right of action for aiding and abetting violations of securities laws. This will foster a stronger culture of integrity and ethical conduct in the auditing profession. An additional tool is to increase financial literacy in our law schools which supply the regulators of our markets