Is gravitational mass of a composite quantum body equivalent to its energy?

We define passive gravitational mass operator of a hydrogen atom in the post-Newtonian approximation of general relativity and show that it does not commute with energy operator, taken in the absence of gravitational field. Nevertheless, the equivalence between the expectation values of passive gravitational mass and energy is shown to survive for stationary quantum states. Inequivalence between passive gravitational mass and energy at a macroscopic level results in time dependent oscillations of the expectation values of passive gravitational mass for superpositions of stationary quantum states, where the equivalence restores after averaging over time. Inequivalence between gravitational mass and energy at a microscopic level reveals itself as unusual electromagnetic radiation, emitted by the atoms, supported and moved in the Earth gravitational field with constant velocity using spacecraft or satellite, which can be experimentally measured.     

Physical origin of observed nonlinearities in Poly(1-naphthyl methacrylate):Using a single transistor–transistor logic modulated laser beam

A thermal lens technique is adopted using a single modulated continuous wave(cw)532-nm laser beam to evaluate the nonlinear refractive index n2,and the thermo-optic coefficient dn/dT,in polymer Poly(1-naphthyl methacrylate)(P-1-NM)dissolved in chloroform,tetrahydrofuran(THF),and dimethyl sulfoxide(DMSO)solvents.The results are compared with Z-scan and diffraction ring techniques.The comparison reveals the effectiveness and the simplicity of the TTL modulation technique.The physical origin is discussed for the obtained results.     

What can a heavy U(1)B-L Z'boson do to the muon(g-2)u anomaly and to a new Higgs boson mass?

The minimal U(1)B_L extension of the Standard Model(B-L-SM)offers an explanation for neutrino mass generatio n via a seesaw mechanism;it also offers two new physics states,namely an extra Higgs bos on and a new Z'gauge boson.The emerge nee of a second Higgs particle as well as a new Z'gauge boson,both lin ked to the breaking of a local U(1)B_L symmetry,makes the B-L-SM rather constrained by direct searches in Large Hadron Collider(LHC)experiments.We investigate the phenomenological status of the B-L-SM by confr on ting the new physics predictions with the LHC and electroweak precision data.Taking into account the current bounds from direct LHC searches,we demonstrate that the prediction for the muon(g-2)u anomaly in the B-L-SM yields at most a contribution of approximately 8.9×10^-12,which represents a tension of 3.28 standard deviations,with the current 1σuncertainty,by means of a Z'boson if its mass is in the range of 6.3 to 6.5 TeV,within the reach of future LHC runs.This means that the B-L-SM,with heavy yet allowed Z‘bos on mass range,in practice,does not resolve the tension between the observed anomaly in the muon(g-2)u and the theoretical prediction in the Standard Model.Such a heavy Z'boson also implies that the minimal value for the new Higgs mass is of the order of 400 GeV.     

What can a heavy U(1)_(B-L) Z' boson do to the muon(g-2)_μ anomaly and to a new Higgs boson mass?

The minimal U(1)_(B-L) extension of the Standard Model(B-L-SM) offers an explanation for neutrino mass generation via a seesaw mechanism;it also offers two new physics states,namely an extra Higgs boson and a new Z' gauge boson.The emergence of a second Higgs particle as well as a new Z' gauge boson,both linked to the breaking of a local U(1)_(B-L) symmetry,makes the B-L-SM rather constrained by direct searches in Large Hadron Collider(LHC) experiments.We investigate the phenomenological status of the B-L-SM by confronting the new physics predictions with the LHC and electroweak precision data.Taking into account the current bounds from direct LHC searches,we demonstrate that the prediction for the muon(g-2)_μ anomaly in the B-L-SM yields at most a contribution of approximately 8.9 × 10~(-12),which represents a tension of 3.28 standard deviations,with the current1σ uncertainty,by means of a Z' boson if its mass is in the range of 6.3 to 6.5 TeV,within the reach of future LHC runs.This means that the B-L-SM,with heavy yet allowed Z' boson mass range,in practice,does not resolve the tension between the observed anomaly in the muon(g-2)_μ and the theoretical prediction in the Standard Model.Such a heavy Z' boson also implies that the minimal value for the new Higgs mass is of the order of 400 GeV.     

Is a wind turbine a point source? (L)

Measurements show that practically all noise of wind turbine noise is produced by turbine blades, sometimes a few tens of meters long, despite that the model of a point source located at the hub height is commonly used. The plane of rotating blades is the critical location of the receiver because the distances to the blades are the shortest. It is shown that such location requires certain condition to be met. The model is valid far away from the wind turbine as well.     

Violation of the Greisen-Zatsepin-Kuzmin cutoff: a tempest in a (magnetic) Teapot? Why cosmic ray energies above 10(20) eV may not require new physics

The apparent lack of suitable astrophysical sources for the observed highest energy cosmic rays within approximately 20 Mpc is the "Greisen-Zatsepin-Kuzmin (GZK) paradox." We constrain representative models of the extragalactic magnetic field structure by Faraday rotation measurements; limits are at the microG level rather than the nG level usually assumed. In such fields, even the highest energy cosmic rays experience large deflections. This allows nearby active galactic nuclei (possibly quiet today) or gamma ray bursts to be the source of ultrahigh energy cosmic rays without contradicting the GZK distance limit.     

Ideal Gas with a Varying (Negative Absolute) Temperature: an Alternative to Dark Energy?

The present work is an attempt to investigate whether the evolutionary history of the Universe from the offset of inflation can be described by assuming the cosmic fluid to be an ideal gas with a specific gas constant but a varying negative absolute temperature (NAT). The motivation of this work is to search for an alternative to the “exotic” and “supernatural” dark energy (DE). In fact, the NAT works as an “effective quintessence” and there is need to deal neither with exotic matter like DE nor with modified gravity theories. For the sake of completeness, we release some clarifications on NATs in Section 3 of the paper.     

Why Noether Symmetry of F(R) Theory Yields Three-Half Power Law?

Noether symmetry of F(R) theory of gravity in vacuum or in matter dominated era yields $F(R) \propto R^{\frac{3}{2}}$ . We show that this particular curvature invariant term is very special in the context of isotropic and homogeneous cosmological model as it makes the first fundamental form h _ij cyclic. As a result, it allows a unique power law solution, typical for this particular fourth order theory of gravity, both in the vacuum and in the matter dominated era. This power law solution has been found to be quite good to explain the early stage but not so special and useful to explain the late stage of cosmological evolution. The usefulness of Palatini variational technique in this regard has also been discussed.     

The ππ S-wave in the 1 to 2 GeV region from a ππ,\bar K K and ρρ(ωω) coupled channel model

A simpleππ, $\bar K$ K, andρρ(ωω) fully coupled channel model is proposed to predict the isoscalarS-wave phase shifts and inelasticities forππ scattering in the 1.0 to 2.0 GeV region. TheS- matrix is required to exhibit poles corresponding to the established isoscalarJ ^π=0⁺ resonancesf ₀(975),f ₀(1400), andf ₀(1710). A dominant feature of the experimentalππ inelasticity is the clear opening of the $\bar K$ K channel near 1 GeV, and the opening of another channel in the 1.4–1.5 GeV region. The success of our model in predicting this observed dramatic energy dependence indicates that the effect of multipion channels is adequately described by theππ coupling to the $\bar K$ K channel, theρρ(4π) andωω(6π) channels.     

Can D'yakonov–Perel' effect cause spin dephasing in GaAs(110) quantum wells?

Current theory [Fiz. Tekh. Popluprovodn. 20 (1986) 178; Sov. Phys. Semicond. 20 (1986) 110] indicates that the D'yakonov–Perel' (DP) mechanism is unable to cause spin dephasing in quantum well (QW) with [110] growth direction. We point out that this is no longer true when the many-body inhomogeneous broadening effect of the DP term is taken into account. Based on our many-body theory [J. Supercond. 14 (2001) 245], by solving the kinetic Bloch equations, we show that the DP term contributes to the spin dephasing in (110) QW. The spin dephasing is also compared with that in (100) QW.     

Can X(5568) be a tetraquark state?

Very recently, the D0 collaboration has reported the observation of a narrow structure, X(5568), in the decay process X(5568)→ B_s~0π±using the 10.4fb~(-1) data of pp collision at 8~(1/2) = 1.96 TeV. This structure is of great interest since it is the first hadronic state with four different valence quark flavors, b, s, u, d. In this work,we investigate tetraquarks with four different quark flavors. Based on the diquark-antidiquark scheme, we study the spectroscopy of the tetraquarks with one heavy bottom/charm quark and three light quarks. We find that the lowest-lying S-wave state, a tetraquark with the flavor [su][bd] and the spin-parity JP= 0~+, is about 150 MeV higher than the X(5568). Further detailed experimental and theoretical studies of the spectrum, production and decays of tetraquark states with four different flavors are vital to gain a better understanding of the nature and classification of hadron exotic states.     

The angular dislocation parallel to a free surface. Application to a (1 1 1)Si low-angle twist boundary

The elastic displacement field of a sharply angular dislocation with its two legs parallel to a planar free surface is given in a practical analytical form. Its expression gives access, in transmission electron microscopy (TEM), to computed images of numerous interacting dislocations all located at a distance h close to the free surface. As an application, this field is used repeatedly to study, in dark-field TEM and a g(3g) diffraction mode with g{2?2?0}, the contrast of dissociated triple nodes of a low-angle twist boundary in silicon extended over a (1?1?1) plane. It is shown that free surface elastic effects can influence the contrasts of some 30° partials if h is at the nanometer scale.