Search Results (12)

Although the gravitational interaction between matter and antimatter has been the subject of theoretical speculation since the discovery of the latter in 1928, only recently was the ALPHA experiment at CERN able to observe, for the first time, the effects of gravity on antimatter atoms, namely on antihydrogen. After an introduction of the concept of antimatter, along with its still-unresolved mysteries, details about how antihydrogen is produced at the Antimatter Factory at CERN will be given. Finally, the measurement of the acceleration of gravity of antihydrogen atoms falling in the Earth’s gravitational field will be described. Full article

We recently proved that in our model of quantum gravity, the solutions to the quantized version of the full Einstein equations or to the Wheeler–DeWitt equation could be expressed as products of spatial and temporal eigenfunctions, or eigendistributions, of self-adjoint operators acting in corresponding separable Hilbert spaces. Moreover, near the big bang singularity, we derived sharp asymptotic estimates for the temporal eigenfunctions. In this paper, we show that, by using these estimates, there exists a complete sequence of unitarily equivalent eigenfunctions which can be extended past the singularity by even or odd mirroring as sufficiently smooth functions such that the extended functions are solutions of the appropriately extended equations valid in $\mathbb{R}$ in the classical sense. We also use this phenomenon to explain the missing antimatter. Full article

In this work, the author employs the quantum hydrodynamic formalism to achieve the geometrization of spacetime for describing the gravitational interaction within the framework of quantum theory. This approach allows for the development of an equation of gravity that is mathematically connected to the fermion and boson fields. This achievement is accomplished by incorporating two fundamental principles: covariance of the quantum field equations and the principle of least action. By considering these principles, a theory is established that enables the calculation of gravitational corrections to quantum electrodynamics and, potentially, to the standard model of particle physics as well. The theory also provides an explanation for two phenomena: the existence of a cosmological pressure density similar to quintessence, which is compatible with the small value of the observed cosmological constant, and the breaking of matter–antimatter symmetry at high energies, offering insights into why there is an imbalance between the two in the early universe. In the cosmological modeling of the theory, there exists a proposal to account for the formation of supermassive black holes that are accompanied by their own surrounding galaxies, without relying on the process of mass accretion. The model, in accordance with recent observations conducted by the James Webb Space Telescope, supports the notion that galactic configurations were established relatively early in the history of the universe, shortly after the occurrence of the Big Bang. Full article

In this talk, I discuss a possible future for the global muon physics program. I focus on the future of flavor studies, precision measurements and searches that can be pursued with a new class of muonium beam sources, and emerging practical applications of muons in the industrial, academic, and government sectors. Full article

In this paper, we study the matter–antimatter imbalance in the universe through baryogenesis (also known as baryosynthesis), which is a physical process that took off just a little while after the big bang explosion, producing a supremacy of matter over antimatter. In this work, we commit the reproduction of the baryon to entropy ratio ($\frac{{\eta }_{{}_B}}{S}=\frac{{\eta }_{{}_{\beta }}-{\eta }_{\overline{{}_{\beta }}}}{S}$), where ${\eta }_{{}_{\beta }}\left({\eta }_{\overline{{}_{\beta }}}\right)$ is a baryon(anti-baryon) number and S is the entropy of the universe in the presence of modified Hořava-Lifshitz $F\left(R\right)$ gravity, which is also called $F\left(\tilde{R}\right)$-gravity. We inspect different baryogenesis interactions proportional to $\tilde{R}$ (where $\tilde{R}$ is the argument of general function F used for the development of modified Hořava-Lifshitz gravity). For this study, we examine two models by choosing different values of $F\left(\tilde{R}\right)$. In the first model, the functional value of $F\left(\tilde{R}\right)=\tilde{R}+\alpha {\tilde{R}}^2$ (where $\alpha$ is a real constant). The second model is more generalized and extended as compare to first one. Mathematically, this model is given by $F\left(\tilde{R}\right)=\tilde{R}+\alpha {\tilde{R}}^2+\beta {\tilde{R}}^m$, where $\alpha$, $\beta$ are real constants and $m>2$ is a real model parameter. Our results for both models and different values of m point out that matter-antimatter asymmetry does not vanish under the effect of the modified Hořava-Lifshitz theory of gravity, which shows a consistent and compatible fact of gravitational baryogenesis with recent observational data. Full article

Advances in cosmology and astronomical observations have brought to light significant tensions and uncertainties within the current model of cosmology, which assumes a spatially flat Universe and is known as the ΛCDM model. Moreover, the Planck Legacy 2018 release has preferred that the early Universe had a positive curvature with a confidence level more than 99%. This study reports a quantum mechanism that could potentially replace the concept of dark matter/energy by taking into the account the primordial curvature while generating the present-day spatial flatness. The approach incorporates the primordial curvature as the background curvature to extend the field equations into brane-world gravity. It utilizes a new wavefunction of the Universe that propagates in the bulk with respect to the scale factor and curvature radius of the early Universe upon the emission of the cosmic microwave background. The resulting wavefunction yields both positive and negative solutions, revealing the presence of a pair of entangled wavefunctions as a manifestation of the creation of matter and antimatter sides of the Universe. The wavefunction shows a nascent hyperbolic expansion away from early energy in opposite directions followed by a first decelerating expansion phase during the first ~10 Gyr and a subsequent accelerating expansion phase in reverse directions. During the second phase, both Universe sides are free-falling towards each other under gravitational acceleration. The simulation of the predicted background curvature evolution shows that the early curved background caused galaxies to experience external fields, resulting in the fast orbital speed of outer stars. Finally, the wavefunction predicts that the Universe will eventually undergo a rapid contraction phase resulting in a Big Crunch, which reveals a cyclic Universe. Full article

Relativistic deformed kinematics are usually considered a way to capture the residual effects of a fundamental quantum gravity theory. These kinematics present a non-commutative addition law for the momenta so that the total momentum of a multi-particle system depends on the specific ordering in which the momenta are composed. We explore in the present work how this property may be used to generate an asymmetry between particles and antiparticles through a particular ordering prescription, resulting in a violation of $CPT$ symmetry. We study its consequences for muon decay, obtaining a difference in the lifetimes of the particle and the antiparticle as a function of the new high-energy scale, parameterizing such relativistic deformed kinematics. Full article

We propose a method by which one could use modified antimatter gravity experiments in order to perform a high-precision test of antimatter charge neutrality. The proposal is based on the application of a strong, external, vertically oriented electric field during an antimatter free-fall gravity experiment in the gravitational field of the Earth. The proposed experimental setup has the potential to drastically improve the limits on the charge-asymmetry parameter ${\overline{ϵ}}_q$ of antimatter. On the theoretical side, we analyze possibilities to describe a putative charge-asymmetry of matter and antimatter, proportional to the parameters ${ϵ}_q$ and ${\overline{ϵ}}_q$, by Lagrangian methods. We found that such an asymmetry could be described by four-dimensional Lorentz-invariant operators that break CPT without destroying the locality of the field theory. The mechanism involves an interaction Lagrangian with field operators decomposed into particle or antiparticle field contributions. Our Lagrangian is otherwise Lorentz, as well as PT invariant. Constraints to be derived on the parameter ${\overline{ϵ}}_q$ do not depend on the assumed theoretical model. Full article

The application of the CPT (charge-conjugation, parity, and time reversal) theorem to an apple falling on Earth leads to the description of an anti-apple falling on anti–Earth (not on Earth). On the microscopic level, the Dirac equation in curved space-time simultaneously describes spin-$1/2$ particles and their antiparticles coupled to the same curved space-time metric (e.g., the metric describing the gravitational field of the Earth). On the macroscopic level, the electromagnetically and gravitationally coupled Dirac equation therefore describes apples and anti-apples, falling on Earth, simultaneously. A particle-to-antiparticle transformation of the gravitationally coupled Dirac equation therefore yields information on the behavior of “anti-apples on Earth”. However, the problem is exacerbated by the fact that the operation of charge conjugation is much more complicated in curved, as opposed to flat, space-time. Our treatment is based on second-quantized field operators and uses the Lagrangian formalism. As an additional helpful result, prerequisite to our calculations, we establish the general form of the Dirac adjoint in curved space-time. On the basis of a theorem, we refute the existence of tiny, but potentially important, particle-antiparticle symmetry breaking terms in which possible existence has been investigated in the literature. Consequences for antimatter gravity experiments are discussed. Full article

The gravitational acceleration of antimatter, $\overline{g}$ , has yet to be directly measured; an unexpected outcome of its measurement could change our understanding of gravity, the universe, and the possibility of a fifth force. Three avenues are apparent for such a measurement: antihydrogen, positronium, and muonium, the last requiring a precision atom interferometer and novel muonium beam under development. The interferometer and its few-picometer alignment and calibration systems appear feasible. With 100 nm grating pitch, measurements of $\overline{g}$ to 10%, 1%, or better can be envisioned. These could constitute the first gravitational measurements of leptonic matter, of 2nd-generation matter, and possibly, of antimatter. Full article

The Standard-Model Extension (SME) provides a comprehensive effective field-theory framework for the study of CPT and Lorentz symmetry. This work reviews the structure and philosophy of the SME and provides some intuitive examples of symmetry violation. The results of recent gravitational tests performed within the SME are summarized including analysis of results from the Laser Interferometer Gravitational-Wave Observatory (LIGO), sensitivities achieved in short-range gravity experiments, constraints from cosmic-ray data, and results achieved by studying planetary ephemerids. Some proposals and ongoing efforts will also be considered including gravimeter tests, tests of the Weak Equivalence Principle, and antimatter experiments. Our review of the above topics is augmented by several original extensions of the relevant work. We present new examples of symmetry violation in the SME and use the cosmic-ray analysis to place first-ever constraints on 81 additional operators. Full article