Long range correlations in DNA: scaling properties and charge transfer efficiency

We address the relation between long-range correlations and charge transfer efficiency in aperiodic artificial or genomic DNA sequences. Coherent charge transfer through the highest occupied molecular orbital states of the guanine nucleotide is studied using the transmission approach, and the focus is on how the sequence-dependent backscattering profile can be inferred from correlations between base pairs.     

Modern Michelson-Morley experiment using cryogenic optical resonators

We report on a new test of Lorentz invariance performed by comparing the resonance frequencies of two orthogonal cryogenic optical resonators subject to Earth's rotation over approximately 1 yr. For a possible anisotropy of the speed of light c, we obtain Delta(theta)c/c(0)=(2.6+/-1.7)x10(-15). Within the Robertson-Mansouri-Sexl (RMS) test theory, this implies an isotropy violation parameter beta-delta-1 / 2=(-2.2+/-1.5)x10(-9), about 3 times lower than the best previous result. Within the general extension of the standard model of particle physics, we extract limits on seven parameters at accuracies down to 10(-15), improving the best previous result by about 2 orders of magnitude.     

Mixing and condensation in a wet granular medium

We have studied the effect of small amounts of added liquid on the dynamic behavior of a granular system consisting of a mixture of glass beads of two different sizes. Segregation of the large beads to the top of the sample is found to depend in a nontrivial way on the liquid content. A transition to viscoplastic behavior occurs at a critical liquid content, which depends upon the bead size. We show that this transition can be interpreted as a condensation due to the hysteretic liquid bridge forces connecting the beads, and we provide the corresponding phase diagram.     

Towards formation of buckminsterfullerene C60 in quantum chemical molecular dynamics

We present follow-up studies on the formation mechanism of fullerene molecules from random ensembles of C2 molecules using quantum chemical molecular dynamics. Two possible roadmaps are investigated as to how buckminsterfullerene C60 and higher fullerenes could be formed. In a "size-up" scenario, fullerenes of the cage size of C72-C96 were found to form directly from high concentrations of C2 molecules at 2000 K with periodic supply of batches of additional C2's. In a "size-down" approach, smaller fullerenes are sometimes formed by losing carbon fragments in "fall-off" or "pop-out" annealing processes under prolonged heating of giant fullerenes, which were self-assembled at initial stages from C2's with lower concentrations. Both roadmaps are found to provide explanations for the appearance of C60 and larger fullerenes in combustion and carbon arc experiments.     

On a conjecture of S.P. Robinson

In his thesis, S.P. Robinson made a conjecture concerning the polynomials

     

Long Time Propagation and Control on Scarring for Perturbed Quantized Hyperbolic Toral Automorphisms

We show that on a suitable time scale, logarithmic in the coherent states on the two-torus, evolved under a quantized perturbed hyperbolic toral automorphism, equidistribute on the torus. We then use this result to obtain control on the possible strong scarring of eigenstates of the perturbed automorphisms by periodic orbits. Our main tool is an adapted Egorov theorem, valid for logarithmically long times. Communicated by Jens Marklof submitted 08/12/04, accepted 11/01/05     

Application of radiative electron capture for the diagnostics of spin-polarized ion beams at storage rings

It is proposed to apply the radiative electron capture into high-Z projectiles as a probe process for measuring the spin polarization of the hydrogenlike ions at storage rings. We argue that such polarization measurements are possible since the linear polarization of emitted x-ray photons is greatly sensitive to the spin states of incoming ions with nuclear spin I > 1/2. In particular, for K-shell electron capture into the hydrogenlike ions, the linear polarization of light as measured out of the reaction plane is found to be proportional to the degree of ion polarization. Detailed computations for the dependence of the photon polarization on the ion spin states and projectile energies are carried out for the electron recombination into hydrogenlike Bi 82+ ions.     

Muon decay: measurement of the transverse polarization of the decay positrons and its implications for the fermi coupling constant and time reversal invariance

The two transverse polarization components P(T1) and P(T2) of the e(+) from the decay of polarized mu(+) have been measured as a function of the e(+) energy. Their energy averaged values are P(T1)=(6.3+/-7.7+/-3.4) x 10(-3) and P(T2)=(-3.7+/-7.7+/-3.4) x 10(-3). From the energy dependence of P(T1) and P(T2) the decay parameters eta,eta(') and alpha(')/A,beta(')/A are derived, respectively. Assuming only one additional coupling besides the dominant V-A interaction one gets improved limits on eta, beta(')/A, and the scalar coupling constant g(S)(RR): eta=(-2.1+/-7.0+/-1.0) x 10(-3), beta(')/A=(-1.3+/-3.5+/-0.6) x 10(-3), Re{g(S)(RR)}=(-4.2+/-14.0+/-2.0) x 10(-3), and Im{g(S)(RR)}=(5.2+/-14.0+/-2.4) x 10(-3).     

Two-photon fourth-order polarimetery

We demonstrate a fourth-order polarimeter that employs two-photon detection to measure the fourth-order polarization coherency matrix (FOCM) of an optical signal. We measure the FOCM of picosecond pulses subjected to polarization mode dispersion (PMD). The fourth-order polarimeter distinguishes different PMD states even when the state of polarization, including the degree of polarization, is constant.