SCOAP3 Repository
https://repo.scoap3.org
SCOAP3 Repository latest documentsenThu, 18 Jul 2019 20:29:26 GMTInvenio 1.1.4.1330-44020repo.admin@scoap3.org3608125https://repo.scoap3.org/img/site_logo_rss.pngSCOAP3 Repository
https://repo.scoap3.org
Search Search this site:p
https://repo.scoap3.org/search
Perspectives on Decay and Time Evolution of Metastable States: From Particle Physics to Cosmology
https://repo.scoap3.org/record/29694
Urbanowski, K.Wed, 12 Dec 2018 21:16:25 GMThttps://repo.scoap3.org/record/29694urn:ISSN:1687-7365Hindawi2018-12-12From Quantum Unstable Systems to the Decaying Dark Energy: Cosmological Implications
https://repo.scoap3.org/record/27465
We consider a cosmology with decaying metastable dark energy and assume that a decay process of this metastable dark energy is a quantum decay process. Such an assumption implies among others that the evolution of the Universe is irreversible and violates the time reversal symmetry. We show that if we replace the cosmological time t appearing in the equation describing the evolution of the Universe by the Hubble cosmological scale time, then we obtain time dependent Λ(t) in the form of the series of even powers of the Hubble parameter H : Λ(t)=Λ(H) . Our special attention is focused on radioactive-like exponential form of the decay process of the dark energy and on the consequences of this type decay.Szydłowski, MarekThu, 23 Aug 2018 13:51:56 GMThttps://repo.scoap3.org/record/27465Hindawi2018-08-19Quantum mechanical look at the radioactive-like decay of metastable dark energy
https://repo.scoap3.org/record/22878
We derive the Shafieloo, Hazra, Sahni and Starobinsky (SHSS) phenomenological formula for the radioactive-like decay of metastable dark energy directly from the principles of quantum mechanics. To this aim we use the Fock–Krylov theory of quantum unstable states. We obtain deeper insight on the decay process as having three basic phases: the phase of radioactive decay, the next phase of damping oscillations, and finally the phase of power-law decay. We consider the cosmological model with matter and dark energy in the form of decaying metastable dark energy and study its dynamics in the framework of non-conservative cosmology with an interacting term determined by the running cosmological parameter. We study the cosmological implications of metastable dark energy and estimate the characteristic time of ending of the radioactive-like decay epoch to be 2.2×104 of the present age of the Universe. We also confront the model with astronomical data which show that the model is in good agreement with the observations. Our general conclusion is that we are living in the epoch of the radioactive-like decay of metastable dark energy which is a relict of the quantum age of the Universe.Szydłowski, MarekSat, 23 Dec 2017 23:57:50 GMThttps://repo.scoap3.org/record/22878urn:ISSN:1434-6052Springer/Società Italiana di Fisica2017-12-23Non-classical Behavior of Moving Relativistic Unstable Particles
https://repo.scoap3.org/record/21603
We study the survival probability of moving relativistic unstable particles with definite momentum $\vec{p} \neq 0$. The amplitude of the survival probability of these particles is calculated using its integral representation. We found decay curves of such particles for the quantum mechanical models considered. These model studies show that late time deviations of the survival probability of these particles from the exponential form of the decay law, that is the transition times region between exponential and non-expo\-nen\-tial form of the survival probability, should occur much earlier than it follows from the classical standard approach resolving itself into replacing time $t$ by $t/\gamma$ (where $\gamma$ is the relativistic Lorentz factor) in the formula for the survival probability and that the survival probabilities should tend to zero as $t\rightarrow \infty$ much slower than one would expect using classical time dilation relation. Here, we show also that for some physically admissible models of unstable states, the computed decay curves of the moving particles have a fluctuating form at relatively short times including times of the order of the lifetime.Urbanowski, K.Fri, 22 Sep 2017 07:10:27 GMThttps://repo.scoap3.org/record/21603urn:ISSN:0587-4254Jagiellonian University2017-08-01Cosmological implications of the transition from the false vacuum to the true vacuum state
https://repo.scoap3.org/record/20287
We study cosmology with running dark energy. The energy density of dark energy is obtained from the quantum process of transition from the false vacuum state to the true vacuum state. We use the Breit–Wigner energy distribution function to model the quantum unstable systems and obtain the energy density of the dark energy parametrization ρde(t) . We also use Krauss and Dent’s idea linking properties of the quantum mechanical decay of unstable states with the properties of the observed Universe. In the cosmological model with this parametrization there is an energy transfer between dark matter and dark energy. The intensity of this process, measured by a parameter α , distinguishes two scenarios. As the Universe starts from the false vacuum state, for the small value of α ( 0<α<0.4 ) it goes through an intermediate oscillatory (quantum) regime of the density of dark energy, while for α>0.4 the density of the dark energy jumps down. In both cases the present value of the density of dark energy is reached. From a statistical analysis we find this model to be in good agreement with the astronomical data and practically indistinguishable from the Λ CDM model.Stachowski, AleksanderWed, 31 May 2017 09:16:32 GMThttps://repo.scoap3.org/record/20287urn:ISSN:1434-6052Springer/Società Italiana di Fisica2017-5-30On the Velocity of Moving Relativistic Unstable Quantum Systems
https://repo.scoap3.org/record/13294
We study properties of moving relativistic quantum unstable systems. We show that in contrast to the properties of classical particles and quantum stable objects the velocity of freely moving relativistic quantum unstable systems cannot be constant in time. We show that this new quantum effect results from the fundamental principles of the quantum theory and physics: it is a consequence of the principle of conservation of energy and of the fact that the mass of the quantum unstable system is not defined. This effect can affect the form of the decay law of moving relativistic quantum unstable systems.Urbanowski, K.Fri, 01 Jan 2016 09:16:02 GMThttps://repo.scoap3.org/record/13294urn:ISSN:1687-7365Hindawi Publishing Corporation2015-12-31Decay law of relativistic particles: Quantum theory meets special relativity
https://repo.scoap3.org/record/3905
Late time properties of moving relativistic particles are studied. Within the proper relativistic treatment of the problem we find decay curves of such particles and we show that late time deviations of the survival probability of these particles from the exponential form of the decay law, that is the transition times region between exponential and non-exponential form of the survival amplitude, occur much earlier than it follows from the classical standard approach boiled down to replace time t by t/γL (where γL is the relativistic Lorentz factor) in the formula for the survival probability. The consequence is that fluctuations of the corresponding decay curves can appear much earlier and much more unstable particles have a chance to survive up to these times or later. It is also shown that fluctuations of the instantaneous energy of the moving unstable particles have a similar form as the fluctuations in the particle rest frame but they are seen by the observer in his rest system much earlier than one could expect replacing t by t/γL in the corresponding expressions for this energy and that the amplitude of these fluctuations can be even larger than it follows from the standard approach. All these effects seem to be important when interpreting some accelerator experiments with high energy unstable particles and the like (possible connections of these effects with GSI anomaly are analyzed) and some results of astrophysical observations.Urbanowski, K.Wed, 03 Sep 2014 20:56:50 GMThttps://repo.scoap3.org/record/3905urn:ISSN:0370-2693Elsevier2014-10-07Possible emission of cosmic X - and γ -rays by unstable particles at late times
https://repo.scoap3.org/record/1458
We find that charged unstable particles as well as neutral unstable particles with non-zero magnetic moment which live sufficiently long may emit electromagnetic radiation. This new mechanism is connected with the properties of unstable particles at the post exponential time region. Analyzing the transition times region between exponential and non-exponential form of the survival amplitude it is found that the instantaneous energy of the unstable particle can take very large values, much larger than the energy of this state for times from the exponential time region. Based on the results obtained for the model considered, it is shown that this purely quantum mechanical effect may be responsible for causing unstable particles to emit electromagnetic-, X - or γ -rays at some time intervals from the transition time regions.Urbanowski, K.Wed, 26 Feb 2014 14:16:28 GMThttps://repo.scoap3.org/record/1458urn:ISSN:0370-2693Elsevier2014-04-04