A String Theory Which Isn't About Strings

Quantization of closed string proceeds with a suitable choice of worldsheet vacuum. A priori, the vacuum may be chosen independently for left-moving and right-moving sectors. We construct {\sl ab initio} quantized bosonic string theory with left-right asymmetric worldsheet vacuum and explore its consequences and implications. We critically examine the validity of new vacuum and carry out first-quantization using standard operator formalism. Remarkably, the string spectrum consists only of a finite number of degrees of freedom: string gravity (massless spin-two, Kalb-Ramond and dilaton fields) and two massive spin-two Fierz-Pauli fields. The massive spin-two fields have negative norm, opposite mass-squared, and provides a Lee-Wick type extension of string gravity. We compute two physical observables: tree-level scattering amplitudes and one-loop cosmological constant. Scattering amplitude of four dilatons is shown to be a rational function of kinematic invariants, and in $D=26$ factorizes into contributions of massless spin-two and a pair of massive spin-two fields. The string one loop partition function is shown to perfectly agree with one loop Feynman diagram of string gravity and two massive spin-two fields. In particular, it does not exhibit modular invariance. We critically compare our construction with recent studies and contrast differences.Comment: 42 pages, 1 figure, minor corrections, references added; v3: minor corrections, references added, published version in JHE

Energy spectra and photoluminescence of fractional quantum Hall systems containing a valence-band hole

The energy spectrum of a two-dimensional electron gas (2DEG) interacting with a valence-band hole is studied in the high magnetic field limit as a function of the filling factor nu and the separation d between the electron and hole layers. For d smaller than the magnetic length lambda, the hole binds one or more electrons to form neutral (X) or charged (X-) excitons. The low-lying states can be understood in terms of Laughlin-like correlations among the constituent charged fermions (electrons and X-). For d comparable to lambda, the electron-hole interaction is not strong enough to bind a full electron, and fractionally charged excitons hQEn (bound states of a hole and one or more Laughlin quasielectrons, QE) are formed. The effect of these excitonic complexes on the photoluminescence spectrum is studied numerically for a wide range of values of nu and d.Comment: 15 pages, 5 figures, submitted to Phil.Mag.

Can a "credit crunch" be efficient?

Two observations have sometimes been viewed as evidence that the equilibrium allocations of intermediated credit markets are inefficient. First, low-income households' marginal propensity to consume is close to unity. Second, even high-income households seem to face nonprice constraints during recessions. This paper presents a model that possesses both of these features. (A recession is modeled as an economy in which the equilibrium level of investment is at its lowest possible level.) However, contrary to the conventional view, the equilibrium of this model is ex ante efficient. The model also sheds light on some historical episodes of credit restraint.Credit

A New Approach to Non-Abelian Hydrodynamics

We present a new approach to describe hydrodynamics carrying non-Abelian macroscopic degrees of freedom. Based on the Kaluza-Klein compactification of a higher-dimensional neutral dissipative fluid on a group manifold, we obtain a d=4 colored dissipative fluid coupled to Yang-Mills gauge field. We calculate the transport coefficients of the new fluid, which show the non-Abelian character of the gauge group. In particular, we obtain group-valued terms in the gradient expansions and response quantities such as the conductivity matrix and the chemical potentials. While using SU(2) for simplicity, this approach is applicable to any gauge group. Resulting a robust description of non-Abelian hydrodynamics, we discuss some links between this system and quark-gluon plasma and fluid/gravity duality.Comment: 41 pages (31 + appendices), 1 figure. V2: Minor modifications, some typos fixed and references adde

Local and Nonlocal Contents in N-qubit generalized GHZ states

We investigate local contents in $N$-qubit generalized Greenberger, Horne, and Zeilinger (GHZ) states. We suggest a decomposition for correlations in the GHZ states into a nonlocal and fully local part, and find a lower and upper bound on the local content. Our lower bound reproduces the previous result for N=2 [Scarani, Phys. Rev. A. 77, 042112 (2008)] and decreases rapidly with $N$.Comment: 4 pages; 1 figure; figure regenerated; upper bound added; a few more clarification