119256430
Remnants, fermions’ tunnelling and effects of quantum gravity
A bstractThe remnants are investigated by fermions’ tunnelling from a 4-dimensional charged dilatonic black hole and a 5-dimensional black string. Based on the generalized uncertainty principle, effects of quantum gravity are taken into account. The quantum numbers of the emitted fermions affects the Hawking temperatures. For the black hole, the quantum gravity correction slows down the increase of the temperature, which leads to the remnant left in the evaporation. For the black string, the existence of the remnant is determined by the quantum gravity correction and effects of the extra compact dimension.
1154617
Stress Tensors in p-adic String Theory and Truncated OSFT
We construct the stress tensors for the p-adic string model and for the pure tachyonic sector of open string field theory by naive metric covariantization of the action. Then we give the concrete energy density of a lump solution of the p-adic model. In the cubic open bosonic string field theory, we also give the energy density of a lump solution and pressure evolution of a rolling tachyon solution.
13902096
Dilaton deformations in closed string field theory
The dilaton theorem implies that the contribution to the dilaton potential from cubic interactions of all levels must be cancelled by the elementary quartic self-coupling of dilatons. We use this expectation to test the quartic structure of closed string field theory and to study the rules for level expansion. We explain how to use the results of Moeller to compute quartic interactions of states that, just like the dilaton, are neither primary nor have a simple ghost dependence. Our analysis of cancellations is made richer by discussing simultaneous dilaton and marginal deformations. We find evidence for two facts: as the level is increased quartic interactions become suppressed and closed string field theory may be able to describe arbitrarily large dilaton deformations.
118539816
Superluminal Neutrinos and Monopoles
In this letter, we show that superluminal neutrinos announced by OPERA could be explained by the existence of a monopole, which is left behind after the spontaneous symmetry breaking (SSB) phase transition of some scalar fields in the universe. We assume the 't Hooft-Polyakov monopole couples to the neutrinos but not photon fields. The monopole introduces a different effective metric to the neutrinos from the one experienced by photons. We find that the superluminal propagation only exists in a very short distance from the monopole, about $10^3$ cm in OPERA. No matter how far they travel, neutrinos always arrive earlier than photons by the same amount of time, provided a monopole existing on or close to their trajectories. This conclusion can be tested by future experiments. The result reconciles the contradiction between OPERA and supernova neutrinos. We further exclude cosmic strings as a possible theoretical explanation.
55601550
Fermion's Tunnelling with Effects of Quantum Gravity
In this paper, using Hamilton-Jacobi method, we address the tunnelling of fermions in a 4-dimensional Schwarzschild spacetime. Based on the generalized uncertainty principle, we introduce 
the influence of quantum gravity. After solving the equation of motion of the spin-1/2 field, we 
derive the corrected Hawking temperature. It turns out that the correction depends not only on 
the black hole’s mass but also on the mass (energy) of emitted fermions. It is of interest that, in 
our calculation, the quantum gravity correction decelerates the temperature increase during the radiation 
explicitly. This observation then naturally leads to the remnants in black hole evaporation. 
Our calculation shows that the residue mass is , where is the Planck mass and is a dimensionless parameter accounting for quantum gravity effects. The evaporation singularity is 
then avoided.
55495910
Homogeneous Field and WKB Approximation in Deformed Quantum Mechanics with Minimal Length
In the framework of the deformed quantum mechanics with a minimal length, we consider the motion of a nonrelativistic particle in a homogeneous external field. We find the integral representation for the physically acceptable wave function in the position representation. Using the method of steepest descent, we obtain the asymptotic expansions of the wave function at large positive and negative arguments. We then employ the leading asymptotic expressions to derive the WKB connection formula, which proceeds from classically forbidden region to classically allowed one through a turning point. By the WKB connection formula, we prove the Bohr-Sommerfeld quantization rule up to . We also show that if the slope of the potential at a turning point is too steep, the WKB connection formula is no longer valid around the turning point. The effects of the minimal length on the classical motions are investigated using the Hamilton-Jacobi method. We also use the Bohr-Sommerfeld quantization to study statistical physics in deformed spaces with the minimal length.
119253042
Emergent Geometry and Quantum Gravity
We explain how quantum gravity can be defined by quantizing spacetime itself. A pinpoint is that the gravitational constant $G = L_{\rm P}^2$ whose physical dimension is of (length)2 in natural unit introduces a symplectic structure of spacetime which causes a noncommutative spacetime at the Planck scale LP. The symplectic structure of spacetime M leads to an isomorphism between symplectic geometry (M, ω) and Riemannian geometry (M, g) where the deformations of symplectic structure ω in terms of electromagnetic fields F = dA are transformed into those of Riemannian metric g. This approach for quantum gravity allows a background independent formulation where spacetime as well as matter fields is equally emergent from a universal vacuum of quantum gravity which is thus dubbed as the quantum equivalence principle.
119236650
Emergent gravity and the cosmological constant problem
We address issues on the origin of gravity and the cosmological constant problem based on a recent understanding about the correspondence between noncommutative field theory and gravity. We suggest that the cosmological constant problem can be resolved in a natural way if gravity emerges from a gauge theory in noncommutative spacetime. Especially, we elucidate why the emergent gravity implies that vacuum energy does not gravitate but only fluctuations around the vacuum generate gravity. That is, a flat spacetime emerges from uniform condensation of energy, previously identified with the cosmological constant.
6820928
Noncommutative electromagnetism as a large N gauge theory
We map noncommutative (NC) U(1) gauge theory on ℝCd×ℝNC2n to U(N→∞) Yang–Mills theory on ℝCd, where ℝCd is a d-dimensional commutative spacetime while ℝNC2n is a 2n-dimensional NC space. The resulting U(N) Yang–Mills theory on ℝCd is equivalent to that obtained by the dimensional reduction of (d+2n)-dimensional U(N) Yang–Mills theory onto ℝCd. We show that the gauge-Higgs system (Aμ,Φa) in the U(N→∞) Yang–Mills theory on ℝCd leads to an emergent geometry in the (d+2n)-dimensional spacetime whose metric was determined by Ward a long time ago. In particular, the 10-dimensional gravity for d=4 and n=3 corresponds to the emergent geometry arising from the 4-dimensional ${\mathcal{N}}=4$ vector multiplet in the AdS/CFT duality. We further elucidate the emergent gravity by showing that the gauge-Higgs system (Aμ,Φa) in half-BPS configurations describes self-dual Einstein gravity.
14739636
High-precision absolute distance measurement using dual-laser frequency scanned interferometry under realistic conditions
In this paper, we report on new high-precision absolute distance measurements performed with frequency scanned interferometry using a pair of single-mode optical fibers. Absolute distances were determined by counting the interference fringes produced while scanning the frequencies of the two chopped lasers. High-finesse Fabry–Perot interferometers were used to determine frequency changes during scanning. Dual lasers with oppositely scanning directions, combined with a multi-distance-measurement technique previously reported, were used to cancel drift errors and to suppress vibration effects and interference fringe uncertainties. Under realistic conditions, a precision about 0:2mm was achieved for a distance of 0.41 m. With a precision that exceeds requirements, the frequency scanned interferometry is a promising high-precision optical alignment technique for International Linear Collider silicon tracker detector.
18270173
Identified particle production in p + p and d +Au collisions at RHIC
The BRAHMS experiment at RHIC has measured the transverse momentum spectra of charged pions, kaons and (anti-)protons over a wide range of rapidity in d+Au and p+p collisions at √SNN = 200 GeV. The nuclear modification factor R dAu at forward rapidity shows a clear suppression for π + . The measured net-proton yields in p+p collisions are compared to PYTHIA and HIJING/B and seem to be better described by the latter.