Transplanckian collisions in TeV scale gravity

Collisions at transplanckian energies offer model independent tests of TeV scale gravity. One spectacular signal is given by black-hole production, though a full calculation of the corresponding cross-section is not yet available. Another signal is given by gravitational elastic scattering, which may be less spectacular but which can be nicely computed in the forward region using the eikonal approximation. In this talk I discuss the distinctive signatures of eikonalized scattering at future accelerators.     

Measurements of a Machian transient mass fluctuation

The prediction of a novel transient mass fluctuation expected in relativistic theories of gravitation that satisfy the globally-local Mach condition (that the cosmic gravitational potential is roughly equal to the square of the speed of light) is set forth. Cosmological consequences of the Mach condition are mentioned, and an experiment that tests the prediction is discussed. The apparatus, procedure, and results of this experiment are described. The predicted effect is seen with better than order of magnitude accuracy.     

A new experimental approach to Mach's principle and relativistic graviation

As noted many years ago by Sciama, and more recently by Nordtvedt, Lorentz invariant (relativistic) gravitation at linear order involves a vector potential that is required to properly account for large inertial effects as well as the correct prediction of the classical tests of general relativity theory (GRT). It is pointed out that the linear-order vector aspect of the gravitational potential makes possible a simple, powerful and inexpensive technique for testing the predictions of GRT and associated issues. An experiment using this technique gives preliminary results that, to order of magnitude, corroborate GRT.1. If one demands a theory that satisfies Mach's Principle irrespective of the particular value of _c, one must go to a theory that contains GRT with critical cosmic matter density as a special case. Such a theory (an Einstein-Cartan theory with teleparallelism) has been developed by Treder [2].2. Equation (4) here is Nordtvedt's Eq. (14), in Ref. 3, with GRT PPN parameters chosen.3. The exact value of this correction factor that depends on the way in which energy is distributed between field and sources in turn depends on how the source term for the gravitational field equations is constructed. At least two different source terms that give correct predictions for the various tests of GRT exist. In this connection see Peters [4]. This ambiguity does not mean that it is impossible in principle to determine how energy is distributed between sources and field. Indeed, if one posits the existence of critical cosmic matter density, this experiment can decide the issue.     

Synthesis and Structure of One Novel Polyoxometalate Compound Connected via Cerium(Ⅲ) Cation with Three-dimensional Framework H2{[K(H2O)2]2[Ce(H2O)5]2(H2Mo1.16W10.84O42)}·8H2O

One novel polyoxometalate compound connected via trivalent cerium cation as bridge H2{[K(H2O)2]2[Ce(H2O)5]2(H2Mo1.16W10.84O42)}·8H2O 1 was designed and synthesized in aqueous solution. X-ray diffraction analysis reveals that the structure of 1 is a three-dimensional framework assembled from the arrangement of H2Mo1.16W10.84O42 (named paradodecmetalate-B) and Ce(H2O)53 containing two planes, which are constructed through the unification of H2Mo1.16W10.84O4210- and Ce(H2O)53 along the [100] and [001] directions. Crystal data: H96Ce4K4Mo2.32O128W21.68, Mr = 7074.89, monoclinic, P21/n, a = 12.5037(17), b = 17.002(2), c = 12.7473(17) (A), β = 105.966(2)°, V = 2605.4(6) (A)3, Z = 1, Dc = 4.509 g/cm3, F(000) = 3132, μ = 26.098 mm(1, R = 0.0377 and wR = 0.0789 (I ＞ 2σ(I)).     

The Uniqueness of the World

We follow some wild speculations in trying to understand the uniqueness of our physical world, from the field concept to F-TheoryDedicated to Emilio Santos on his 70th birthday. I have enjoyed discussions with Emilio on physics for the last 40 years; in spite of disagreements on many issues, I have an everlasting admiration for him and for his approach to science     

Modified entropic gravitation in superconductors

Verlinde recently developed a theoretical account of gravitation in terms of an entropic force. The central element in Verlinde’s derivation is information and its relation with entropy through the holographic principle. The application of this approach to the case of superconductors requires to take into account that information associated with superconductor’s quantum vacuum energy is not stored on Planck size surface elements, but in four volume cells with Planck-Einstein size. This has profound consequences on the type of gravitational force generated by the quantum vacuum condensate in superconductors, which is closely related with the cosmological repulsive acceleration responsible for the accelerated expansion of the Universe. Remarkably this new gravitational type force depends on the level of breaking of the weak equivalence principle for cooper pairs in a given superconducting material, which was previously derived by the author starting from similar principles. It is also shown that this new gravitational force can be interpreted as a surface force. The experimental detection of this new repulsive gravitational-type force appears to be challenging.     

New fermions at the LHC and mass of the Higgs boson

Unification at MGUT∼3×¹⁰¹⁶ GeV$M_{\mathrm{GUT}}\sim 3\times {10}^{16}\text{GeV}$ of the three Standard Model (SM) gauge couplings can be achieved by postulating the existence of a pair of vectorlike fermions carrying SM charges and masses of order 300 GeV–1 TeV. The presence of these fermions significantly modifies the vacuum stability and perturbativity bounds on the mass of the SM Higgs boson. The new vacuum stability bound in this extended SM is estimated to be 117 GeV, to be compared with the SM prediction of about 128 GeV. An upper bound of 190 GeV is obtained based on perturbativity arguments. The impact on these predictions of type I seesaw physics is also discussed. The discovery of a relatively ‘light’ Higgs boson with mass ∼117 GeV$\sim 117\text{GeV}$ could signal the presence of new vectorlike fermions within reach of the LHC.     

Geodesic‐invariant equations of gravitation

Einstein's equations of gravitation are not invariant under geodesic mappings, i.e. under a certain class of mappings of the Christoffel symbols and the metric tensor which leave the geodesic equations in a given coordinate system invariant. A theory in which geodesic mappings play the role of gauge transformations is considered.     

Quantum Correlations,Nuclearity, and Spacetime Curvature

It is proved for a Haag–Araki–Kastler quantum field theory, that gravitation reduces the correlations in the vacuum state. Secondly, we prove Bell's inequalities by nuclearity assumptions. The so-called -content of certain compact mappings restricts the size of the set of measurements which violate Bell's inequalities.     

潮汐现象的成因

讨论了引潮力的成因，太阳的引潮力与月亮的引潮力的相对大小，并对潮汐现象的一些规律和影响因素作了简要介绍。