The effect of quantum fluctuations in compact star observables

Astrophysical measurements regarding compact stars are just ahead of a big evolution jump, since the NICER experiment deployed on ISS on 14 June 2017. This will soon provide data that would enable the determination of compact star radius with less than 10% error. This poses new challenges for nuclear models aiming to explain the structure of super dense nuclear matter found in neutron stars. Detailed studies of the QCD phase diagram shows the importance of bosonic quantum fluctuations in the cold dense matter equation of state. Here, we using a demonstrative model to show the effect of bosonic quantum fluctuations on compact star observables such as mass, radius, and compactness. We have also calculated the difference in the value of compressibility which is caused by quantum fluctuations. The above mentioned quantities are calculated in mean field, one-loop and in high order many-loop approximation. The results show that the magnitude of these effects is ~5%, which place it into the region where forthcoming high-accuracy measurements may detect it.Comment: 6 pages 4 figues, minor corrections were adde

FRG Approach to Nuclear Matter at Extreme Conditions

Functional renormalization group (FRG) is an exact method for taking into account the effect of quantum fluctuations in the effective action of the system. The FRG method applied to effective theories of nuclear matter yields equation of state which incorporates quantum fluctuations of the fields. Using the local potential approximation (LPA) the equation of state for Walecka-type models of nuclear matter under extreme conditions could be determined. These models can be tested by solving the corresponding Tolman--Oppenheimer--Volkov (TOV) equations and investigating the properties (mass and radius) of the corresponding compact star models. Here, we present the first steps on this way, we obtained a Maxwell construction within the FRG-based framework using a Walecka-type Lagrangian.Comment: 6 pages, 3 figure

The effect of air-fuel equivalence ratio change on the vibration components of an internal-combustion engine

Nowadays the automotive industry and the motor development are one of the most dynamically developing industries. One solution to the diagnostic systems providing reliability is the acoustic and vibration measurement system, which can indicate and predict a variety of malfunctions after signal processing. The purpose of this experiment is to analyze the effect of the air-fuel equivalence ratio on the vibration components of an internal-combustion engine (ICE) which is a part of the in question measurement system. In the focus of the experiments are the analysis of the time signal, its spectra, and the power content of the signal. With the increment of the air-fuel ratio the amplitudes of the measured signal and its spectral amplitudes showed a downward trend as the RMS values. In addition, certain frequency components disappeared during the actuation of the ICE with an electromotor, so the characterization of the combustion could be come to the front

A szubkontinentális litoszféraköpeny nagy mélységeiben lejátszódó fluidmigrációs folyamatok összehasonlító vizsgálata = Comparative study of the fluid migration processes in the deep lithospheric mantle

A kutatás során a köpenyben nagy mélységben migráló C-O-H fluidumok szerepét vizsgáltuk a köpenymetaszomatózis és gyémántkristályosodás folyamataiban. Negyvennél több, dél Afrikából származó diamondit xenolitot elemeztünk; meghatároztuk a gyémánttal összenőtt gránátot és klinopiroxént fő- és nyomelem (LAM-ICPMS) tartalmát, valamint a gyémánt C és N izotóparányait. A diamonditban található gránátok 5 csoportra oszthatók: peridotitos, átmeneti és 3 eklogitos (E1, E2, E3) csoportokra. A P gránátot tartalmazó diamondit karbonatit-kimberlit összetételű fluidumból kristályosodott, míg az E gránátot tartalmazó diamonditot kristályosító fluidum nyomelemei az alkáli bazaltokhoz hasonlítanak. A gyémántot kristályosító fluidumok redukált szenet tartalmazó mély köpeny eredetű fluidumokból oxidáció révén képződtek. Ez a folyamat C izotóp frakcionációval járt. Az így képződött karbonatit fejlődött tovább, és kristályosította a P és E típusú diamonditokat. Természetes és szintetikus karbonát-eklogit rendszeren végeztünk kísérlekete 8.5 GPa nyomáson és 1700-1800 oC hőmérsékleten. A kis viszkozitású karbonát olvadék gyorsan eljutott a gyémántkristályosodás helyére, nagyfokú gyémántkristályosodás volt megfigyelhető, és a gyémántokkal együtt gránát és cpx is kristályosodott. A természetes diamondit xenolitok vizsgálata és a kísérleti eredmények megerősítik, hogy a kontitnentális kratonok mélyén a gyémánt kristályosodás karbonatitos közegben megy végbe a köpenymetaszomatózis eredményeképp. | Migration of C-O-H fluids in the subcontinental lithospheric mantle and their role in mantle metasomatism and crystallization diamondites have been studied. Garnet and clinopyroxene intergrowths from over 40 diamondite xenoliths from southern Africa have been analysed form major and trace elements (LAM-ICPMS), and diamonds have been analysed for C and N isotope ratios. Five garnet groups could be distinguished: peridotitic, transitional and 3 eclogitic (E1, E2,E3). Diamondites with P garnets crystallised from fluids in the carbonatite-kimberlite spectrum, while the parental fluids for diamondites with E garnets had trace element composition similar to alkali basalts. Parental fluids for diamondites evolved from reduced carbon species of deep mantle origin through oxidation. The resulted carbonatitic melt would further evolve and crystallize the P and E diamondites. Experiments on natural and synthetic carbonate-eclogite systems have been made at 8.5 GPa and 1700-1800 oC in order to simulate processes for the formation of diamondites. The processes observed are as follows: quick migration of mobile low-viscosity carbonate-silicate melts into zones of diamondite formation, extremely high rate of diamondite crystallization from a carbonate- silicate melt and formation of syngenetic inclusions of garnet and cpx inside the pores and cavities of diamondites. Diamondites crystallised in carbonatitic environment as a result of mantle metasomatism in the roots of the cratons