Search results for "gravitaatio"

On the carrier of inertia

2018

A change in momentum will inevitably perturb the all-embracing vacuum, whose reaction we understand as inertia. Since the vacuum's physical properties relate to light, we propose that the vacuum embodies photons, but in pairs without net electromagnetic fields. In this physical form the free space houses energy in balance with the energy of matter in the whole Universe. Likewise, we reason that a local gravitational potential is the vacuum in a local balance with energy that is bound to a body. Since a body couples to the same vacuum universally and locally, we understand that inertial and gravitational masses are identical. By the same token, we infer that gravity and electromagnetism shar…

On the exhaust of electromagnetic drive

2016

Recent reports about propulsion without reaction mass have been met on one hand with enthusiasm and on the other hand with some doubts. Namely, closed metal cavities, when fueled with microwaves, have delivered thrust that could eventually maintain satellites on orbits using solar power. However, the measured thrust appears to be without any apparent exhaust. Thus the Law of Action-Reaction seems to have been violated. We consider the possibility that the exhaust is in a form that has so far escaped both experimental detection and theoretical attention. In the thruster's cavity microwaves interfere with each other and invariably some photons will also end up co-propagating with opposite pha…

The 1-loop effective potential for the Standard Model in curved spacetime

2018

The renormalisation group improved Standard Model effective potential in an arbitrary curved spacetime is computed to one loop order in perturbation theory. The loop corrections are computed in the ultraviolet limit, which makes them independent of the choice of the vacuum state and allows the derivation of the complete set of $\beta$-functions. The potential depends on the spacetime curvature through the direct non-minimal Higgs-curvature coupling, curvature contributions to the loop diagrams, and through the curvature dependence of the renormalisation scale. Together, these lead to significant curvature dependence, which needs to be taken into account in cosmological applications, which i…

Massless positivity in graviton exchange

2021

We formulate Positivity Bounds for scattering amplitudes including exchange of massless particles. We generalize the standard construction through dispersion relations to include the presence of a branch cut along the real axis in the complex plane for the Maldestam variable $s$. In general, validity of these bounds require the cancellation of divergences in the forward limit of the amplitude, proportional to $t^{-1}$ and $\log(t)$. We show that this is possible in the case of gravitons if one assumes a Regge behavior of the amplitude at high energies below the Planck scale, as previously suggested in the literature, and that the concrete UV behaviour of the amplitude is uniquely determined…

Space and Time Averaged Quantum Stress Tensor Fluctuations

2021

We extend previous work on the numerical diagonalization of quantum stress tensor operators in the Minkowski vacuum state, which considered operators averaged in a finite time interval, to operators averaged in a finite spacetime region. Since real experiments occur over finite volumes and durations, physically meaningful fluctuations may be obtained from stress tensor operators averaged by compactly supported sampling functions in space and time. The direct diagonalization, via a Bogoliubov transformation, gives the eigenvalues and the probabilities of measuring those eigenvalues in the vacuum state, from which the underlying probability distribution can be constructed. For the normal-orde…

Internetin vaikutus kansainväliseen kaupankäyntiin

2006

Universal Gravitation and the (Un)Intelligibility of Natural Philosophy

2019

This article centers on Hume's position on the intelligibility of natural philosophy. To that end, the controversy surrounding universal gravitation shall be scrutinized. It is very well known that Hume sides with the Newtonian experimentalist approach rather than with the Leibnizian demand for intelligibility. However, what is not clear is Hume's overall position on the intelligibility of natural philosophy. It shall be argued that Hume declines Leibniz's principle of intelligibility. However, Hume does not eschew intelligibility altogether; his concept of causation itself stipulates mechanical intelligibility. peerReviewed

Baryogenesis and gravity waves from a UV-completed electroweak phase transition

2021

We study gravity wave production and baryogenesis at the electroweak phase transition, in a real singlet scalar extension of the Standard Model, including vector-like top partners to generate the CP violation needed for electroweak baryogenesis (EWBG). The singlet makes the phase transition strongly first-order through its coupling to the Higgs boson, and it spontaneously breaks CP invariance through a dimension-5 contribution to the top quark mass term, generated by integrating out the heavy top quark partners. We improve on previous studies by incorporating updated transport equations, compatible with large bubble wall velocities. The wall speed and thickness are computed directly from th…

Newton's Law of Universal Gravitation and Hume's Conception of Causality

2013

This article investigates the relationship between Hume’s causal philosophy and Newton’s philosophy of nature. I claim that Newton’s experimentalist methodology in gravity research is an important background for understanding Hume’s conception of causality: Hume sees the relation of cause and effect as not being founded on a priori reasoning, similar to the way that Newton criticized non-empirical hypotheses about the properties of gravity. However, according to Hume’s criteria of causal inference, the law of universal gravitation is not a complete causal law, since it does not include a reference either to contiguity or to temporal priority. It is still argued that because of the empirical…

Regularisaatio vahvojen gravitaatiolinssien inversiossa

2015

Massiivisten galaksien gravitaatio aiheuttaa vääristymän teleskoopilla havaittavaan kuvaan muuttamalla galaksin takaa saapuvan valon reittiä. Niin kutsu- tuissa vahvoissa gravitaatiolinsseissä voi linssinä toimiva galaksi tuottaa kuvaan sen takana olevasta galaksista useita näyttäviä kaaria. Linssinä toimineen galaksin massa ja linssiytyneen galaksin alkuperäinen muoto voidaan tällöin laskennallisesti selvit- tää, ja näin saada tietoa linssigalaksin massan ja teleskoopilla suoraan havaitun valon määrän suhteesta. Tämän lähtökohtaisesti huonosti määritellyn inversio-ongelman laskennallinen ratkaiseminen vaatii kuitenkin ongelman uudelleenmäärittelyä eli regularisaatiota. Ongelman ratkaisemis…