Repulsive effects in steady axisymmetric fields

In this paper the repulsive effects in the Kerr and Kerr--Newman fields are discussed. The contributions made by all parameters of the fields and test particles to the repulsive effects are also discussed, and the accretive effect on interstellar dust, i.e. the distribution of dust is calculated. The discussion is also carried out on the slow rotation of the Kerr field in which the effect is related to the positions and velocities of the particles and the orientations of their trajectories as well.     

Neutrino oscillation interference phase in Kerr space--time

The mass neutrino interference phases along the null trajectory and the geodesic line in Kerr space--time are studied on the plane θ=π/2. Because of the rotation object in Kerr space--time, a particle travelling along the radial geodesic must have a dragging effect produced by the angular momentum of the central object. We give the correction of the phase due to the rotation of the space--time. We find that the type-I interference phase along the geodesic remains the double of that along the null on the condition that the rotating quantity parameter a² is preserved and the higher order terms are negligible (e.g. a⁴). In addition, we calculate the proper oscillation length in Kerr space--time. All of our results can return to those in Schwarzschild space--time as the rotating parameter a approaches zero.     

New infinite-dimensional symmetry groups for the stationary axisymmetric Einstein--Maxwell equations with multiple Abelian gauge fields

The so-called extended hyperbolic complex (EHC) function method is used to study further the stationary axisymmetric Einstein--Maxwell theory with $p$ Abelian gauge fields (EM-$p$ theory, for short). Two EHC structural Riemann--Hilbert (RH) transformations are constructed and are then shown to give an infinite-dimensional symmetry group of the EM-$p$ theory. This symmetry group is verified to have the structure of semidirect product of Kac--Moody group $\widehat{SU(p+1,1)}$ and Virasoro group. Moreover, the infinitesimal forms of these two RH transformations are calculated and found to give exactly the same infinitesimal transformations as in previous author's paper by a different scheme. This demonstrates that the results obtained in the present paper provide some exponentiations of all the infinitesimal symmetry transformations obtained before.     

整体单极子黑洞引力场中的加速效应

给出了含有整体单极子的黑洞的引力场中试验粒子加速度的表达式, 讨论了整体单极子对加速效应的贡献. 结果表明, 由于整体单极子的存在, 产生了斥力效应; 当速度趋近于光速时, 中性粒子在引力场中受到了斥力作用. 这是牛顿力学中所没有的.     

一般稳态时空中光子的轨道效应

计算了带有电荷和磁荷的旋转场源外部稳态时空中光子的轨道效应. 通过对计算结果的分析, 发现由荷电所引起的光子轨道偏转效应将减小由场源质量所引起的光子轨道偏转效应,但由场源的旋转所引起的相应偏转效应将依赖于场源的旋转方向与光子运动方向之间的夹角. 通过对相应的天体参数的讨论得到了一系列有意义的结果. 关键词： 光子轨道 引力效应 稳态时空     

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。     

Test of the equivalence principle in space

Summary Any violation of the equivalence principle (EP) between test masses in the near-Earth orbit is about 500 times bigger than on the ground, which makes the case for a space experiment very strong. Indeed, ESA and NASA (the European Space Agency and the American National Aeronautics and Space Administration) are currently studying at Phase A level the space mission STEP, whose main goal is to test the universality of free fall to 1 part in 10¹⁷ by means of a combination of very advanced technologies (drag free with proportional thrusters, superfluid-He temperature, SQUID sensors). We discuss the key features of STEP as well as some novel ideas about the possibility of testing the equivalence principle at room temperature in a non-drag-free satellite. Paper presented at the 6th Cosmic Physics National Conference, Palermo, 3–7 November 1992.     

Coincidences among the data recorded by the baksan, kamioka and mont blanc underground neutrino detectors, and by the Maryland and Rome gravitational-wave detectors during Supernova 1987 A

Summary The data recorded with the neutrino detectors at Mont Blanc, Kamioka, Baksan and with the gravitational-wave detectors in Maryland and Rome have been analysed searching for correlations associated with SN 1987 A, without presuming or excluding hypotheses for correlations due to neutrinos and gravitational waves. The statistical analysis has been based on a previous analysis that showed a correlation among Maryland, Rome and Mont Blanc with a probability to be accidental less than 10⁻⁵. Independent correlations are found during a period of one or two hours, around the Mont Blanc 5ν burst (2h 52 min 36 s UT), among the various sets of data: Mont Blanc-Baksan with a probability to be accidental of the order ofp∼4·10⁻³, Mont Blanc-Kamioka withp∼4·10⁻³, Maryland-Rome-Kamioka withp∼5·10⁻⁴, Maryland-Rome-Baksan withp∼5·10⁻². It is remarkable that the events from all the neutrino detectors follow the signals from the g.w. detectors by a time of the order of 1/2 or 1 s. At present we will not give a physical interpretation of the observed correlations which have strong statistical significance. Professor Edoardo Amaldi died on December 5, 1989.     

Sensitivity improvement of a two-mode gravitational-radiation detector through the use of a transducer not perfectly tuned to the antenna

Summary The detailed analysis of the behaviour of a gravitational-wave antenna coupled to a passive resonant transducer has been performed for short bursts of gravitational radiation. An expression for the noise temperature of the system is given for the general case of a transducer with resonant frequency and mechanical quality factor different from those of the antenna. The analysis of the optimum noise temperature obtainable for a given system shows that the optimum performance is obtained when the frequency of the transducer is slightly different from that of the antenna. The main point of this paper has been presented byC. Cosmelli at theSecond Workshop on Precision Measurements on Relativistic Effects in Astrophysical Systems, held in Rome, 11–13 July 1983.     

Upper limit on the flux of gravitational wave bursts

Summary The data obtained with three highly sensitive gravitational wave antennas have been used to establish an improved observational upper limit on the flux of impulsive gravitational waves. Preliminary results under the assumption of a source located in the center of the Galaxy are also reported. To speed up publication, the proofs were not sent to the authors and were superised by the Scientific Committee.     

The abnormal influence of the partial solar eclipse on December 24th, 1992, on the time comparisons between atomic clocks

Summary During the partial solar eclipse on Dec. 24th, 1992, time comparisons between atomic clocks were made: direct comparisons between different clocks at one and the same station, clock transport comparisons, GPS comparisons and LOC comparisons. And it is concluded from the observations that solar eclipse exerts an influence on the rate of atomic clocks. Project Supported by the State Science and Technology Commission of China and by the National Natural Foundation of China.     

SN 1987 A: Correlations between the Maryland and Rome gravitational wave detector data and the Mont Blanc and Kamiokande neutrino detector data

Summary The author reports on the analysis of the data obtained with the detectors given in the title in the period 12h of February 22, 1987 to 6h of February 23, 1987, that includes the time of the ν observation with the Mont Blanc detector during SN 1987a. A very significant correlation has been observed among the data of the above detectors in a period of one or two hours which includes the time of the Mont Blanc 5ν observation. The correlation between the g.w. data and the Kamiokande data is found if a time of 7.8s is added to the Kamioka recorded time; this is very close to the time difference, 6.2s, between the IMB and Kamioka large ν bursts observed at ≈7h 35 min. To speed up publication, the proofs were not sent to the authors and were supervised by the Scientific Committee.     

Wide-band measurement of gravitational waves: the VIRGO project

Summary To detect gravitational waves (GW) in a frequency range between 10 Hz and few kHz a ground-based antenna was designed by the French-Italian collaboration VIRGO. The antenna is a 3 km long interferometer with special suspensions for the optical components, planned to reduce the seismic noise in order to reach the low-frequency region. Results on the seismic isolation devices are given together with some preliminary results on the use of permanent magnets on the VIRGO suspensions. Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990.     

Derivation of Dirac's Equation from the Evans Wave Equation

The Evans wave equation [1] of general relativity is expressed in spinor form, thus producing the Dirac equation in general relativity. The Dirac equation in special relativity is recovered in the limit of Euclidean or flat spacetime. By deriving the Dirac equation from the Evans equation it is demonstrated that the former originates in a novel metric compatibility condition, a geometrical constraint on the metric vector qused to define the Einstein metric tensor. Contrary to some claims by Ryder, it is shown that the Dirac equation cannot be deduced unequivocally from a Lorentz boost in special relativity. It is shown that the usually accepted method in Clifford algebra and special relativity of equating the outer product of two Pauli spinors to a three-vector in the Pauli basis leads to the paradoxical result X = Y = Z = 0. The method devised in this paper for deriving the Dirac equation from the Evans equation does not use this paradoxical result.     

Analysis of 18 months of data of the GEOGRAV experiment

Summary We report on the analysis of 18 months of data of the GEOGRAV experiment: a room temperature gravitational-wave antenna equipped with various sensors of geophysical quantities (accelerometer, gravimeter and electrical antenna). We present results on the search for sidereal periodicities in the background of the gravitational-wave antenna as regards both hourly averages and large-amplitude pulses.

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Riassunto Si riferisce sull'analisi di 18 mesi di dati dell'esperimento GEOGRAV: un'antenna gravitazionale a temperatura ambiente equipaggiata con sensori di grandezze geofisiche (accelerometro, gravimetro ed antenna elettrica). Si presentano risultati sulla ricerca di periodicità siderali nel fondo dell'antenna gravitazionale, per quanto riguarda sia le medie orarie che gli impulsi di grande ampiezza.

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Резюме Мы анализируем данные, полученные в течение 18 месяцев в эксперименте ?GEOGRAV?: антенна гравитационных волн при комнатной температуре, снабженная различными датчиками геофизическин величин (акселерометр, гравиметр и электрическая антенна). Приводятся результаты по поиску сидерических периодичностей в фоне антенны гравитационных волн.

     

The gravitational wave antenna in Frascati

Summary We report on the cryogenic gravitational detector operating at 1763 Hz in Frascati. The antenna was equipped with a resonant capacitive transducer and a d.c. SQUID as an amplifier. After a test run in 1987, the detector was cooled again in the present configuration and took data for nearly two months in June and July 1988. A preliminary data analysis shows a noise temperature of 115 mK, but we expect to lower it further by applying improved filtering tecniques. During the same period two other cryogenic antennae were operating, and we plan to undertake a correlation analysis between the output of the three detectors. To speed up publication, the proofs were not sent to the authors and were supervised by the Scientific Committee.     

Testing deviations from the inverse square law with a freely falling gravity gradiometer at balloon altitudes

Summary We discuss a null experiment to search for the fifth force at ranges around 10 km. It is proposed to use a three-axis gravity gradiometer to measure the trace of the Earth gravity tensor from a freely falling elevator dropped by a balloon. The main error sources are considered to some extent. Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990.     

Effect of baffle on gravity-gradient-excited slosh waves and spacecraft moment and angular-momentum fluctuations in microgravity

Summary The dynamical behavior of fluids affected by the asymmetric gravity gradient acceleration has been investigated. In particular, the effects of surface tension on partially filled rotating fluids applicable to a full-scale Gravity Probe-B Spacecraft dewar tank with and without baffles are studied. Results of slosh wave excitation along the liquid-vapor interface induced by gravity gradient acceleration indicate that the gravity gradient acceleration is equivalent to the combined effect of a twisting force and a torsional moment acting on the spacecraft. The results are clearly seen from one-up one-down and one-down one-up oscillations in the cross-section profiles of two bubbles in the vertical (r, z)-plane of the rotating dewar, and from the eccentric contour of the bubble rotating around the axis of the dewar in a horizontal (r, θ)-plane. As the viscous force, between liquid and solid interface, greatly contributes to the damping of slosh wave excitation, a rotating dewar with baffles provides more areas of liquid-solid interface than that of a rotating dewar without baffles. Results show that the damping effect provided by the baffles reduces the amplitude of slosh wave excitation and lowers the degree of asymmetry in liquid-vapor distribution. Fluctuations of angular momentum and fluid moment caused by the slosh wave excited by gravity gradient acceleration with and without baffle boards are also investigated. It is also shown that the damping effect provided by the baffles greatly reduces the amplitudes of angular momentum and fluid moment fluctuations.     

Preliminary results on the operation of a 2270 kg cryogenic gravitational-wave antenna with a resonant capacitive transducer and a d.c. SQUID amplifier

Summary In November 1985 the gravitational-wave antenna of the Rome group, installed at CERN, has started operating. It consists of a 5056 aluminium cilinder 3 m long, 2270 kg heavy, cooled at 4.2 K. The antenna vibrations are detected by means of a resonant capacitive transducer that together with the bar makes a two-coupled-oscillator system. The low-noise amplification is obtained with a d.c. SQUID amplifier. The frequencies of the two resonant modes are:v _-=907.116 Hz andv ₊=923.083 Hz, with merit factorsQ ₋=3.2·10⁶ andQ ₊=5.6·10⁶. The sensitivity to short gravitational bursts, expressed in terms of effective noise temperature, is 18 mK. This corresponds to a change in the metric tensor whose Fourier transform isH=1.1·10⁻²¹ Hz⁻¹. For monochromatic waves the antenna is sensitive (SNR=1) toh∼2·10⁻²⁵ in a band width of about 1/3 Hz, with a three months integration time.

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Riassunto Nel novembre 1985 è stata messa in funzione l'antenna gravitazionale del gruppo di Roma, installata al CERN. Questa consiste di un cilindro d'alluminio 5056 lungo 3 m e pesante 2270 kg, raffeeddato a 4.2 K. Le vibrazioni dell'antenna vengono rivelate mediante un transduttore capacitivo risonante, che assieme alla sbarra forma un sistema di due oscillatori accoppiati. L'amplificazione a basso rumore è ottenuta con un amplificatore a d.c.-SQUID. Le frequenze dei due modi risonanti sono:v _-=907.116 Hz ev ₊=923.083 Hz, con fattori di meritoQ ₋=3.2·10⁶ eQ ₊ =5.6·10⁶. La sensibilità per brevi fiotti di onde gravitazionali, espressa in termini di temperatura efficace di numore, è 18 mK. Questa corrisponde a una variazione di tensore metrico con trasformata di Fourier:H=1.1·10⁻²¹ Hz. Per le onde monocromatiche l'antenna è sensibile (SNR=1) ah∼2·10⁻²⁵ in una banda di circa 1/3 Hz, con tempo d'integrazione di tre mesi.