引力场中的质量亏损效应

利用Hellings-Nordtvedt理论,我们得到了一类荷磁天体(含宇宙常数)的引力场中质量亏损效应的表达式。通过讨论这些表达式中的参数，我们得到了在不同条件下的质量亏损表达式。这些结果对于天体形成过程中能量辐射机制的研究是有意义的。     

Relativistic gravitational collapse by thermal mass

Gravity and thermal energy are universal phenomena which compete over the stabilization of astrophysical systems.The former induces an inward pressure driving collapse and the latter a stabilizing outward pressure generated by random motion and energy dispersion.Since a contracting self-gravitating system is heated up one may wonder why is gravitational collapse not halted in all cases at a sufficient high temperature establishing either a gravo-thermal equilibrium or explosion.Here,based on the equivalence between mass and energy,we show that there always exists a temperature threshold beyond which the gravitation of thermal energy overcomes its stabilizing pressure and the system collapses under the weight of its own heat.     

Is active gravitational mass equal to inertial mass?

It is possible, within the framework of general relativity, to define an active gravitational mass density of incoherent matter. It is not equal to the inertial mass density, except when at rest. The concept can be specialized to a single massive particle; again, its active gravitational mass is not equal to its inertial mass, except when it rests. A measurement of the impulse imparted to a test particle by a massive body passing nearby can establish the difference, and it may be possible to carry out this measurement in a laboratory. As a by-product of our computations we obtain a generalization to nonradial motion of the slowing-down effect in a Schwarzschild field.     

Inertial and gravitational mass in quantum mechanics

We show that in complete agreement with classical mechanics, the dynamics of any quantum mechanical wave packet in a linear gravitational potential involves the gravitational and the inertial mass only as their ratio. In contrast, the spatial modulation of the corresponding energy wave function is determined by the third root of the product of the two masses. Moreover, the discrete energy spectrum of a particle constrained in its motion by a linear gravitational potential and an infinitely steep wall depends on the inertial as well as the gravitational mass with different fractional powers. This feature might open a new avenue in quantum tests of the universality of free fall.     

Response functions of free mass gravitational wave antennas

Rainer Weiss and collaborators have from first principles derived the response of a free mass interferometer (or 2-arm gravitational wave antenna) to plane polarized gravitational waves [1]. We here obtain equivalent formulas (generalized slightly to allow for arbitrary elliptical polarization) by a simple differencing of the 3-pulse Doppler response functions of two 1-arm antennas [2]. A 4-pulse response function is found, with quite complicated angular dependences for arbitrary incident polarization. The differencing method can as readily be used to write exact response functions (3n+1 pulse!) for antennas having multiple passes, or having more arms.The research described in this paper was carried out at the Jet Propulsion Laboratory, under contract with the National Aeronautics and Space Administration.     

Constraining photon mass by energy-dependent gravitational light bending

Science China Physics, Mechanics & Astronomy - In the standard model of particle physics, photons are massless particles with a particular dispersion relation. Tests of this claim at different...     

The use of mass defect in modern mass spectrometry

Mass defect is defined as the difference between a compound's exact mass and its nominal mass. This concept has been increasingly used in mass spectrometry over the years, mainly due to the growing use of high resolution mass spectrometers capable of exact mass measurements in many application areas in analytical and bioanalytical chemistry. This article is meant as an introduction to the different uses of mass defect in applications using modern MS instrumentation. Visualizing complex mass spectra may be simplified with the concept of Kendrick mass by plotting nominal mass as a function of Kendrick mass defect, based on hydrocarbons subunits, as well as slight variations on this theme. Mass defect filtering of complex MS data has been used for selectively detecting compounds of interest, including drugs and their metabolites or endogenous compounds such as peptides and small molecule metabolites. Several strategies have been applied for labeling analytes with reagents containing unique mass defect features, thus shifting molecules into a less noisy area in the mass spectrum, thus increasing their detectability, especially in the area of proteomics. All these concepts will be covered to introduce the interested reader to the plethora of possibilities of mass defect analysis of high resolution mass spectra.     

On a new gravitational effect of a rotating mass

A new general relativistic many-body effect is described. It results in an unexpectedly large relative acceleration between neighboring test particles that follow an inclined orbit about a rotating mass. The effect vanishes if the orbit coincides with the equatorial plane of the rotating mass. The existence of this effect is due to a small divisor involving the deviation of the orbital frequency measured by a comoving clock from the frequency measured by an inertial clock. The influence of the rotation of the Sun on the Earth-Moon system is investigated, and it is shown that the new effect causes a harmonic variation in the Earth-Moon separation with an amplitude of order 1 m and dominant periods of 18.6 yr, 1/2 yr, 1 month, and 1/2 month. The confirmation of these results by the lunar laser ranging experiment would provide a significant new test of general relativity and a measurement of the angular momentum of the Sun.This essay received the fifth award from the Gravity Research Foundation for the year 1983 [Ed.].     

Minimum mass–radius ratio for charged gravitational objects

We rigorously prove that for compact charged general relativistic objects there is a lower bound for the mass–radius ratio. This result follows from the same Buchdahl type inequality for charged objects, which has been extensively used for the proof of the existence of an upper bound for the mass–radius ratio. The effect of the vacuum energy (a cosmological constant) on the minimum mass is also taken into account. Several bounds on the total charge, mass and the vacuum energy for compact charged objects are obtained from the study of the Ricci scalar invariants. The total energy (including the gravitational one) and the stability of the objects with minimum mass–radius ratio is also considered, leading to a representation of the mass and radius of the charged objects with minimum mass–radius ratio in terms of the charge and vacuum energy only.     

Black hole mass threshold from nonsingular quantum gravitational collapse

Quantum gravity is expected to remove the classical singularity that arises as the end state of gravitational collapse. To investigate this, we work with a toy model of a collapsing homogeneous scalar field. We show that nonperturbative semiclassical effects of loop quantum gravity cause a bounce and remove the black hole singularity. Furthermore, we find a critical threshold scale below which no horizon forms: quantum gravity may exclude very small astrophysical black holes.     

Observational cosmology within the ESA science programme

Summary Several missions of the Science Programme of ESA aim at tackling issues of direct relevance to fundamental questions of modern cosmology. In this paper we are following the arrow of time on a simplified space-time diagram on which we identify the means of observing back in the past the physical phenomena or the structures which occur or appear at various epochs in the evolution of the Universe. We show how ESA through its science missions can contribute to these observations in a unique way. The missions themselves are not described in detail but we give in the text the relevant bibliographical references. To speed up publication, the proofs were not sent to the authors and were supervised by the Scientific Committee     

Relation between gravitational mass and baryonic mass for non-rotating and rapidly rotating neutron stars

With a selected sample of neutron star(NS)equations of state(EOSs)that are consistent with the current observations and have a range of maximum masses,we investigate the relations between NS gravitational mass Mg and baryonic mass and the relations between the maximum NS mass supported through uniform rotation(Mmax)and that of nonrotating NSs(Mtov).We find that for an EOS-independent quadratic,universal transformation formula(Mb=Mg+A×M^2/g),the best-fit A value is 0.080 for non-rotating NSs,0.064 for maximally rotating NSs,and 0.073 when NSs with arbitrary rotation are considered.The residual error of the transformation is?0.1M⊙ for non-spin or maximum-spin,but is as large as?0.2M⊙ for all spins.For different EOSs,we find that the parameter A for non-rotating NSs is proportional to R^-1/1.4(where R1.4 is NS radius for 1.4M⊙ in units of km).For a particular EOS,if one adopts the best-fit parameters for different spin periods,the residual error of the transformation is smaller,which is of the order of O.O1M⊙ for the quadratic form and less than O.O1M⊙ for the cubic form(Mb=Mg+A1×M^2/g+A2×M^3/g).We also find a very tight and general correlation between the normalized mass gain due to spin △m≡(Mmax-MTOV)MTOV and the spin period normalized to the Keplerian period P,i.e.,log10 △m=(-2.74±0.05)log10 P+log10(0.20±0.01),which is independent of EOS models.These empirical relations are helpful to study NS-NS mergers with a long-lived NS merger product using multi-messenger data.The application of our results to GW170817 is discussed.