Physics from information
Department of energy resources development, Jungwon University,5 dongburi, Goesan-eup, Goesan-gun Chungbuk Korea 367-805(Dated: November 9, 2010)This is an ongoing review on my conjecture that information processing at causal horizons isthe key ingredient of all physics. Assuming that information is fundamental and the informationpropagates with ﬁnite velocity, one can ﬁnd that main physical laws such as Newton’s second law andEinstein equation simply describe the energy-information relation (dE=TdS) for matter or spacetime crossing a causal horizon with temperature T for observers. Quantum mechanics arises fromignorance of the observers about matter crossing the horizon, which explains why superluminalcommunication is impossible even with quantum entanglement. This approach also explains theorigin of Jacobson’s thermodynamic formalism of Einstein gravity and Verlinde’s entropic gravity.When applied to a cosmic causal horizon, the conjecture reproduces the observed dark energy anddemands the zero cosmological constant.

title: Dark energy from forgetting
abstract: We suggest that dark energy has a quantum informational origin. Landauer's principle associated with the erasure of quantum information at a cosmic horizon implies the non-zero vacuum energy having effective negative pressure. Assuming the holographic principle, the minimum free energy condition, and the Gibbons-Hawking temperature for the cosmic event horizon we obtain the holographic dark energy with the parameter $d\simeq 1$, which is consistent with the current observational data. It is also shown that both the entanglement energy and the horizon energy can be related to Landauer's principle.

title: Zero cosmological constant and nonzero dark energy from the holographic principle
abstract: The first law of thermodynamics and the holographic principle applied to an arbitrary large cosmic causal horizon are shown to naturally demand a zero cosmological constant and a non-zero dynamical dark energy in the form of the holographic dark energy. A semiclassical analysis shows that the holographic dark energy has a parameter d = 1 and an equation of state comparable to current observational data if the entropy of the horizon saturates the Bekenstein-Hawking bound. This result indicates that quantum field theory should be modified on a large scale to explain the dark energy. The relations among the dark energy, the quantum vacuum energy and the entropic gravity are also discussed.

title: Quantum entanglement from the holographic principle
abstract: It is suggested that quantum entanglement emerges from the holographic principle stating that all of the information of a region (bulk bits) can be described by the bits on its boundary surface. There are redundancy and information loss in the bulk bits that lead to the nonlocal correlation among the bulk bits. Quantum field theory overestimates the independent degrees of freedom in the bulk. The maximum entanglement in the universe increases as the size of the cosmic horizon and this could be related with the arrow of time and dark energy.

title: Dark energy, inflation and the cosmic coincidence problem
abstract: We show that holographic dark energy could explain why the current dark energy density is so small, if there was an inflation with a sufficient expansion in the early universe. It is also suggested that an inflation with the number of e-folds N ≃ 65 may solve the cosmic coincidence problem in this context. Assuming the inflation and the power-law acceleration phase today we obtain approximate formulas for the event horizon size of the universe and dark energy density as functions of time. A simple numerical study exploiting the formula well reproduces the observed evolution of dark energy. This nontrivial match between the theory and the observational data supports both inflation and holographic dark energy models.

title: Radiation Damping at a Bubble Wall
abstract: The first order phase transition proceeds via nucleation and growth of true vacuum bubbles. When charged particles collide with the bubble they could radiate electromagnetic wave. We show that, due to an energy loss of the particles by the radiation, the damping pressure acting on the bubble wall depends on the velocity of the wall even in a thermal equilibrium state.

title: Studies of the Cabibbo-Suppressed Decays D+ -> pi0 lepton+ neutrino and D+ -> eta e+ electron-neutrino
abstract: Using 4.8 fb{sup -1} of data taken with the CLEO II detector, the branching fraction for the Cabibbo suppressed decay D{sup +} {yields} {nu} measured relative to the Cabibbo favored decay D{sup +} {yields} {nu} is found to be 0.046 {+-} 0.014 {+-} 0.017. Using V{sub cs} and V{sub cd} from unitarity constraints, we determine |f{sub +}{sup {pi}}(0)/f{sub +}{sup K} (0)|{sup 2} = 0.9 {+-} 0.3 {+-} 0.3 We also present a 90% confidence level upper limit for the branching ratio of the decay D{sup +} {yields} {eta}e{sup +} relative to that for D{sup +} {yields}  of 1.5.

title: A Measurement of the Michel Parameters in Leptonic Decays of the Tau
abstract: We have measured the spectral shape Michel parameters {rho} and {eta} using leptonic decays of the {tau}, recorded by the CLEO II detector. Assuming e-{mu} universality, we find {rho}{sub e{mu}}= 0.735 {+-} 0.013 {+-} 0.008 and {eta}{sub e{mu}} = 0.015 {+-} 0.061 {+-} 0.062, where the first error is statistical and the second systematic.

title: Note on a Differential-Geometrical Construction of Optimal Directions in Linearly-Constrained Systems
abstract: This note presents an analytic construction of the optimal unit-norm direction b x = x/||x|| that maximizes or minimizes the objective linear expression, Bb x, subject to a system of linear constraints of the form (A) �x = 0, where x is an unknown n-dimensional real vector to be determined up to an overall normalization constant, 0 is an m-dimensional null vector, and the n-dimensional real vector B and the m×n-dimensional real matrix (A) (with 0 ≤ m < n) are given. The analytic solution to this problem can be expressed in terms of a combination of double wedge and Hodge-star products of differential forms.

title: Pre-Flare Activity and Magnetic Reconnection during the Evolutionary Stages of Energy Release in a Solar Eruptive Flare
abstract: In this paper, we present a multi-wavelength analysis of an eruptive white-light M3.2 flare that occurred in active region NOAA 10486 on 2003 November 1. The excellent set of high-resolution observations made by RHESSI and the TRACE provides clear evidence of significant pre-flare activities for ~9 minutes in the form of an initiation phase observed at EUV/UV wavelengths followed by an X-ray precursor phase. During the initiation phase, we observed localized brightenings in the highly sheared core region close to the filament and interactions among short EUV loops overlying the filament, which led to the opening of magnetic field lines. The X-ray precursor phase is manifested in RHESSI measurements below ~30 keV and coincided with the beginning of flux emergence at the flaring location along with early signatures of the eruption. The RHESSI observations reveal that both plasma heating and electron acceleration occurred during the precursor phase. The main flare is consistent with the standard flare model. However, after the impulsive phase, an intense hard X-ray (HXR) looptop source was observed without significant footpoint emission. More intriguingly, for a brief period, the looptop source exhibited strong HXR emission with energies up to ~50-100 keV and significant non-thermal characteristics. The present study indicates a causal relation between the activities in the pre-flare and the main flare. We also conclude that pre-flare activities, occurring in the form of subtle magnetic reorganization along with localized magnetic reconnection, played a crucial role in destabilizing the active region filament, leading to a solar eruptive flare and associated large-scale phenomena.

title: Hard probes in heavy ion collisions at the LHC: heavy flavour physics
abstract: We present the results from the heavy quarks and quarkonia working group. This report gives benchmark heavy quark and quarkonium cross sections for $pp$ and $pA$ collisions at the LHC against which the $AA$ rates can be compared in the study of the quark-gluon plasma. We also provide an assessment of the theoretical uncertainties in these benchmarks. We then discuss some of the cold matter effects on quarkonia production, including nuclear absorption, scattering by produced hadrons, and energy loss in the medium. Hot matter effects that could reduce the observed quarkonium rates such as color screening and thermal activation are then discussed. Possible quarkonium enhancement through coalescence of uncorrelated heavy quarks and antiquarks is also described. Finally, we discuss the capabilities of the LHC detectors to measure heavy quarks and quarkonia as well as the Monte Carlo generators used in the data analysis.