On the number of instabilities of cosmological solutions in an Einstein-Yang-Mills system

A detailed numerical stability analysis of the static, spherically symmetric globally regular solutions of the Einstein-Yang-Mills equations with a positive cosmological constant, Lambda, is carried out. It is found that the number of unstable modes in the even parity sector is n for solutions with n=1,2 nodes as Lambda varies. The solution with n=3 nodes exhibits a rather surprising behaviour in that the number of its unstable modes jumps from 3 to 1 as Lambda crosses (from below) a critical value. In particular the topologically 3-sphere type solution with n=3 nodes has only a single unstable mode.Comment: minor corrections,to appear in Physics Letters

Eccentric first post-Newtonian waveforms for compact binaries in frequency domain with Hansen coefficients

The inspiral and merger of supermassive black hole binary systems with high orbital eccentricity are among the promising sources of the advanced gravitational wave observatories. In this paper we derive analytic ready-to-use first post-Newtonian eccentric waveform in Fourier domain with the use of Hansen coefficients. Introducing generic perturbations of celestial mechanics we have generalized the Hansen expansion to the first post-Newtonian order which are then used to express the waveforms. Taking into account the high eccentricity of the orbit leads to the appearance of secular terms in the waveform which are eliminated with the introduction of a phase shift. The waveforms have a systematic structure and as our main result these are expressed in a tabular form.Comment: 19 pages, 3 figure

Self-gravitating scalar breathers with negative cosmological constant

Breather-type (time-periodic and spatially localized) solutions with spherical symmetry are investigated in a massless scalar field theory coupled to Einstein's gravity with cosmological constant in $d$ spatial dimensions imposing anti de Sitter (AdS) asymptotics on space-time. Using a code constructed with the Kadath library that enables the use of spectral methods, the phase space of breather solutions is explored in detail for $d=3$ and $d=4$. It is found that there are discrete families of solutions indexed by an integer and by their frequency. Using a time evolution code these AdS breathers are found to be stable for up to a critical central density, in analogy to boson stars. Using an analytical perturbative expansion small amplitude breathers are worked out for arbitrary dimensions $d$.Comment: 24 pages, 13 figures, one figure and references added, version accepted for Phys. Rev.

Scalar field breathers on anti-de Sitter background

We study spatially localized, time-periodic solutions (breathers) of scalar field theories with various self-interacting potentials on Anti-de Sitter (AdS) spacetimes in $D$ dimensions. A detailed numerical study of spherically symmetric configurations in $D=3$ dimensions is carried out, revealing a rich and complex structure of the phase-space (bifurcations, resonances). Scalar breather solutions form one-parameter families parametrized by their amplitude, $\varepsilon$, while their frequency, $\omega=\omega(\varepsilon)$, is a function of the amplitude. The scalar breathers on AdS we find have a small amplitude limit, tending to the eigenfunctions of the linear Klein-Gordon operator on AdS. Importantly most of these breathers appear to be generically stable under time evolution.Comment: 30 pages, 22 figure

Radiation of scalar oscillons in 2 and 3 dimensions

The radiation loss of small-amplitude radially symmetric oscillons (long-living, spatially localized, time-dependent solutions) in two- and three-dimensional scalar field theories is computed analytically in the small-amplitude expansion. The amplitude of the radiation is beyond all orders in perturbation theory and it is determined using matched asymptotic series expansions and Borel summation. The general results are illustrated on the case of the two- and three-dimensional sine-Gordon theory and a two-dimensional $\phi^6$ model. The analytic predictions are found to be in good agreement with the results of numerical simulations of oscillons.Comment: 7 pages, 3 figure

Parameter estimation for inspiraling eccentric compact binaries including pericenter precession

Inspiraling supermassive black hole binary systems with high orbital eccentricity are important sources for space-based gravitational wave (GW) observatories like the Laser Interferometer Space Antenna (LISA). Eccentricity adds orbital harmonics to the Fourier transform of the GW signal and relativistic pericenter precession leads to a three-way splitting of each harmonic peak. We study the parameter estimation accuracy for such waveforms with different initial eccentricity using the Fisher matrix method and a Monte Carlo sampling of the initial binary orientation. The eccentricity improves the parameter estimation by breaking degeneracies between different parameters. In particular, we find that the source localization precision improves significantly for higher-mass binaries due to eccentricity. The typical sky position errors are $\sim1$deg for a nonspinning, $10^7\,M_{\odot}$ equal-mass binary at redshift $z=1$, if the initial eccentricity 1 yr before merger is $e_0\sim 0.6$. Pericenter precession does not affect the source localization accuracy significantly, but it does further improve the mass and eccentricity estimation accuracy systematically by a factor of 3--10 for masses between $10^6$ and $10^7\,M_{\odot}$ for $e_0 \sim 0.3$.Comment: 14 two-column pages, 12 figures, expanded version; contains the proof correction

Újabb terápiás lehetőségek a Huntington kór állatmodelljében = Novel therapeutic possibilities in an animal model of Huntington's disease.

A pathomechanizmus vizsgálata: A transzgenetikus állatok motoros aktivitása 12 héttől kezdődően romlott, míg az exploratív magatartásuk már 8 hetes korban csökkent. Az neuroaktív aminosavak szintje szignifikánsan alacsonyabb Huntington kór ill. Parkinson kór modelljében. Ez a csökkenés 24 óra elteltével rendeződött. A Parkinson kóros betegek plazmájában a kinurenin aminotranszferáz (KAT) izoenzimek aktivitása, valamint a kinurénsav (KYNA) szintje is alacsonyabb volt, mint a kontroll csoportban. Fokális dystóniában szenvedő betegek plazmájában KAT izoenzimek aktivitása csökkent, míg aKYNA szintje nem változott. Az agyspecifikus TPPP/p25 protein expressziója nem mutatható ki a transzgentikus egerekben. A glükolízis vizsgálata során az állatokban a GAPDH aktivitása lecsökkent, míg az ATP szint megemelkedett. Ennek további vizsgálata folyamatban van. A terápiás vizsgálatok: (a szabadalmi eljárások miatt a vegyületek pontos nevét jelenleg nem közölhetjük): Egy antioxidáns hatású vizsgálati szer (vizsg. anyag1) és egy transzporter gátló szer (vizsg. anyag2) növelte az állatok túlélését, és késleltette a betegség kialakulását. A neuroprotektív hatás szövettani alátámasztása folyamatban van. Egy proteáz inhibitor (vizsg. anyag3), egy antipszichotikum (vizsg. anyag4) és antioxidáns hatású szer (vizsg. anyag5) is növelte az állatok túlélését, és késleltette a betegség kialakulását. E szerek esetén a szövettani vizsgálatra jelenleg még nincs elegendő állatunk. | Studies on pathomechanism: From 12th weeks of age the motor activities of the transgenic mice deteriorated, while the explorative behavior has been decreased from 8th weeks of age. In a toxin model of Huntington's disease and Parkinson's disease, the levels of neuroactive amino acids decreased, which were recovered after 24 hours. In the plasma of parkinsonian patients the activity of kynurenine aminotransferase (KAT) and the level of kynurenic acid (KYNA) were decreased. In focal dystonia, the KAT activity is decreased in the plasma, while the KYNA level was not changed. The brain specific TPPP/p25 protein can not be detected in the transgenic mice. In transgenic mice the GAPDH activity was decreased, while the ATP level was increased. More studies needed to clarify the data. Therapeutic studies (due to the patent issues the drugs can not be identified): An antioxidant (drug1) and a transporter inhibitor (drug2) increased the survival of the mice and delayed the onset of the symptoms. The histological evaluation of this protective effect is in progress. A protease inhibitor (drug3), a antipsychotic drug (drug4) and an antioxidant expert neuroprotective effects in this model. The histological studies prolonged due to the lack of sufficient number of transgenic mice

Nontopological Solitons in Abelian Gauge Theories Coupled to U(1) x U(1) Symmetric Scalar Fields

In a series of recent works, Ishihara and Ogawa have investigated nontopological solitons (Q-balls) in a spontaneously broken Abelian gauge theory coupled to two complex scalar fields. The present paper extends their investigations to the most general U(1) x U(1) symmetric quartic potential. Also, a new class of charged Q-ball solutions with vanishing self-interaction terms is investigated and some of their remarkable properties are exhibited.We thank Professor Hideki Ishihara for correspondence concerning the numerical methods used in Refs. [19,20]. We acknowledge the support of the Spanish Ministerio de Ciencia, Innovacion y Universidades (Grant No. PCI2018-092896) and the EU (QuantERA Controlling EPR and Bell correlations in Bose-Einstein condensates

Charge Screening in the Abelian Higgs Model

In the Abelian Higgs model electric (and magnetic) fields of external charges (and currents) are screened by the scalar field. In this contribution, complementing recent investigations of Ishihara and Ogawa, we present a detailed investigation of charge screening using a perturbative approach with the charge strength as an expansion parameter. It is shown how perfect global and remarkably good local screening can be derived from Gauss' theorem, and the asymptotic form of the fields far from the sources. The perturbative results are shown to compare favourably to the numerical onesa.L. acknowledges the support of the Spanish Ministerio de Ciencia, Innovacion y Universidades (Grant No. PCI2018-092896) and the EU (QuantERA CEBBEC