We consider the infrared modification of gravity by ghost condensate. Naively, in this scenario one expects sizeable modification of gravity at distances of order 1000 km, provided that the characteristic time scale of the theory is of the order of the Hubble time. However, we argue that this is not the case. The main physical reason for the conspiracy is a simple fact that the Earth (and any o...

We study the the properties of a BRST ghost degree of freedom complementary to a two-state spinor. We show that the ghost may be regarded as a unit carrier of negative entropy. We construct an irreducible representation of the su(2) Lie algebra with negative spin, equal to −12 , on the ghost state space and discuss the representation of finite SU(2) group elements. The Casimir operator J2 of th...

We consider the infrared modification of gravity by ghost condensate. Naively, in this scenario one expects sizeable modification of gravity at distances of order 1000 km, provided that the characteristic time scale of the theory is of the order of the Hubble time. However, we argue that this is not the case. The main physical reason for the conspiracy is a simple fact that the Earth (and any o...

Phage coats or ghosts, composed entirely of protein, appear to be responsible for protecting the phage nucleic acid from degradation by factors in the surrounding medium; attachment of the virus to its susceptible host; and delivering the nucleic acid to the interior of the cell. In addition, the ghosts have a number of biological actions which resemble similar actions of the patent phage. Thus...

We report on an experimental and theoretical investigation of quantum imaging where the images are stored in both space and time. Ghost images of remote objects are produced with either one or two beams of chaotic laser light generated by a rotating ground glass and two sensors measuring the reference field and bucket field at different space-time points. We further observe that the ghost image...

We have searched the broad-absorption-linequasar (BAL QSO) sample presented by Reichard et al. for objects exhibiting the so-called ‘ghost of Lyman alpha’. This ghost manifests as a hump near −5900 km s in the troughs of the broad absorption lines and provides strong evidence for the importance of line-driving in powering the outflows from BAL QSOs. Of the 224 sample BAL QSOs selected from the ...

A fundamental open problem in the area of blockchain protocols is whether the Bitcoin protocol is the only solution for building a secure transaction ledger. A recently proposed and widely considered alternative is the GHOST protocol which, notably, was proposed to be at the core of Ethereum as well as other recent proposals for improved Bitcoin-like systems. The GHOST variant is touted as o er...

We present the theory of a supersymmetric ghost condensate coupled to N = 1 supergravity. This is accomplished using a general formalism for constructing locally supersymmetric higher-derivative chiral superfield actions. The theory admits a ghost condensate vacuum in de Sitter spacetime. Expanded around this vacuum, the scalar sector of the theory is shown to be ghost-free with no spatial grad...

Using the structured serial coalescent with Bayesian MCMC and serial samples, we estimate population size when some demes are not sampled or are hidden, ie ghost demes. It is found that even with the presence of a ghost deme, accurate inference was possible if the parameters are estimated with the true model. However with an incorrect model, estimates were biased and can be positively misleadin...

Introduction: Ghost imaging and especially its applications to MR angiography (MRA) have been proposed as an improvement over the conventional magnitude subtraction based imaging methods, such as Fresh Blood Imaging (FBI) [1]. There are basically two types of ghost MRA; type I and II. Type I is usually performed without gating, by summing outside the body ghost artifacts created from uncontroll...