Ground-state properties of fermionic mixtures with mass imbalance in optical lattices

Ground-state properties of fermionic mixtures confined in a one-dimensional optical lattice are studied numerically within the spinless Falicov-Kimball model with a harmonic trap. A number of remarkable results are found. (i) At low particle filling the system exhibits the phase separation with heavy atoms in the center of the trap and light atoms in the surrounding regions. (ii) Mott-insulating phases always coexist with metallic phases. (iii) Atomic-density waves are observed in the insulating regions for all particle fillings near half-filled lattice case. (iv) The variance of the local density exhibits the universal behavior (independent of the particle filling, the Coulomb interaction and the strength of a confining potential) over the whole region of the local density values.Comment: 10 pages, 5 figure

Congressional Self-Discipline: The Constitutionality of Supermajority Rules

Congress needs to be more disciplined. It has at times become sloppy and even cavalier. When, for example, Congress enacted the federal Gun-Free School Zone Act of 1990, it was asking for trouble. Neither the legislation nor the legislative history said anything about any effect on interstate commerce. It was therefore not surprising to see the Supreme Court strike the law down in United States v. Lopez

Can We Indict a Sitting President?

This symposium addresses the difficult question of whether a President can be criminally prosecuted while still in office or whether indictment and prosecution must await his leaving. The question is difficult because the text of the Constitution gives us some hints but no dispositive answers. At first reading, Section 3 of Article I seems to suggest that impeachment must precede any criminal prosecution: Judgment in Cases of Impeachment shall not extend further than to removal from Office, and disqualification to hold and enjoy any Office of honor, Trust, or Profit under the United States; but the Party convicted shall nevertheless be liable and subject to Indictment, Trial, Judgment and Punishment, according to Law. Thus, the provision suggests it may be prescribing a temporal order - impeachment and then prosecution. However, closer analysis reveals that the provision may simply be defining and limiting the effects of impeachment and making clear that other punishments can be still imposed by the criminal process without violating any prohibitions against double jeopardy; it may not be addressing the issue of order at all