Middlemen: the visible market makers

This paper presents a search-theoretic model where middlemen can emerge endogenously to intermediate between ex ante homogeneous buyers and sellers in the presence of coordination frictions. Middlemen set price to compete in the market, and hold an inventory to provide a high matching service. I show that middlemen's inventories can mitigate trade imbalances and interact with price competition, generating an interesting tradeoff for the equilibrium price determination. The competitive limit emerges when middlemen guarantee excess demand will never occur. Conditions are characterized under which middlemen carry out the short-side principle for the market price to be Walrasian

Inflation, price competition and consumer search technology

This paper studies an (S, s) pricing model from the perspective of inflation and price competition in search markets. I present a model in which consumers'search technologies can influence firms' price setting, price dispersion, and the market structure. The result shows that although price competition among firms is more intensified in markets where consumers' search technologies are more efficient, price inflation is counter-intuitively, more likely to increase monopoly power of firms and to stimulate entry in these markets. The model also provides new empirical implications for firms' price setting behaviors

Superconducting SET with tunable electromagnetic environment

We have studied the environmental effect on superconducting single-electron transistors (S-SETs) by biasing S-SETs with arrays of small-capacitance dc SQUIDs, whose effective impedance can be varied in situ. As the zero-bias resistance of the arrays is increased, Coulomb blockade in the S-SET becomes sharper, and the gate-voltage dependence changes from e-periodic to 2e-periodic. The SQUID arrays could be used as on-chip noise filters.Comment: 2 pages, 3 embedded figures, submitted to LT23 proceedings. Error in Fig. 1 has been fixe

Tax Policy and Consumer Spending: Evidence from Japanese Fiscal Experiments

This paper studies the extent to which the impact of tax policy on consumer spending differs between temporary and permanent, as well as anticipated and unanticipated tax changes. To discriminate between them, we use institutional information such as legal distinction between temporary and permanent tax changes, as well as timing of policy announcement and implementation. We find that the impact of temporary changes is significantly smaller than the impact of permanent changes. We also find that more than 80 per cent of Japanese consumers, including those who distinguish between temporary and permanent tax changes, respond to tax changes at the time of their implementation and not at the time of a policy announcement. We suggest an interpretation that these consumers follow a near-rational decision rule.

The solution to the BCS gap equation and the second-order phase transition in superconductivity

The existence and the uniqueness of the solution to the BCS gap equation of superconductivity is established in previous papers, but the temperature dependence of the solution is not discussed. In this paper, in order to show how the solution varies with the temperature, we first give another proof of the existence and the uniqueness of the solution and point out that the unique solution belongs to a certain set. Here this set depends on the temperature $T$. We define another certain subset of a Banach space consisting of continuous functions of both $T$ and $x$. Here, $x$ stands for the kinetic energy of an electron minus the chemical potential. Let the solution be approximated by an element of the subset of the Banach space above. We second show, under this approximation, that the transition to a superconducting state is a second-order phase transition.Comment: Journal of Mathematical Analysis and Applications, in pres

Reversal of the circulation of a vortex by quantum tunneling in trapped Bose systems

We study the quantum dynamics of a model for a vortex in a Bose gas with repulsive interactions in an anisotropic, harmonic trap. By solving the Schr\"odinger equation numerically, we show that the circulation of the vortex can undergo periodic reversals by quantum-mechanical tunneling. With increasing interaction strength or particle number, vortices become increasingly stable, and the period for reversals increases. Tunneling between vortex and antivortex states is shown to be described to a good approximation by a superposition of vortex and antivortex states (a Schr\"odinger cat state), rather than the mean-field state, and we derive an analytical expression for the oscillation period. The problem is shown to be equivalent to that of the two-site Bose Hubbard model with attractive interactions.Comment: 5 pages, 5 figures; published in Phys. Rev. A, Rapid Communication

Non-equilibrium Relaxation Analysis on Two-dimensional Melting

The melting transition in the hard-disk system is considered. Non-equilibrium relaxation analysis of the six-fold bond-orientational order parameter has been carried out. The critical point between the hexatic and the fluid phase is determined on the basis of the dynamic scaling hypothesis. The value of the critical exponent $\eta$ is determined from the fluctuation of the order parameter at the criticality as $\eta = 0.25(2)$ which is consistent with the prediction by the Kosterlitz-Thouless-Halperin-Nelson-Young theory.Comment: 8 pages, 5 figures. submitted to Prog. Theor. Phys. Suppl. as a proceedings of Symposium on the 50th anniversary of the Alder transitio