Equilibrium and Disorder-induced behavior in Quantum Light-Matter Systems

We analyze equilibrium properties of coupled-doped cavities described by the Jaynes-Cummings- Hubbard Hamiltonian. In particular, we characterize the entanglement of the system in relation to the insulating-superfluid phase transition. We point out the existence of a crossover inside the superfluid phase of the system when the excitations change from polaritonic to purely photonic. Using an ensemble statistical approach for small systems and stochastic-mean-field theory for large systems we analyze static disorder of the characteristic parameters of the system and explore the ground state induced statistics. We report on a variety of glassy phases deriving from the hybrid statistics of the system. On-site strong disorder induces insulating behavior through two different mechanisms. For disorder in the light-matter detuning, low energy cavities dominate the statistics allowing the excitations to localize and bunch in such cavities. In the case of disorder in the light- matter coupling, sites with strong coupling between light and matter become very significant, which enhances the Mott-like insulating behavior. Inter-site (hopping) disorder induces fluidity and the dominant sites are strongly coupled to each other.Comment: about 10 pages, 12 figure

Is there a significant change in the price transmission between producer and retail prices within the British Pork industry?

The purpose of this study is to examine price transmission between the producer and retail in the UK pork industry. It aims to find the direction of causality in the long and short-run, and whether there is a long-run relationship between producer and retail prices. This study used monthly time series data for producer and retail prices ranging from 1988-2016. Econometric tests were used such as the Augmented Dickey-Fuller (1979) and Phillips-Perron (1988) Unit Root tests; Bai-Perron (1998) Unit Root test allowing for multiple structural breaks; Johansen (1991) and Engle-Granger (1987) Co-integration tests; Granger (1988) Causality, and the Error Correction Model showing the speed of recovery in the long-run relationship after a shock. The results of the Unit Root tests found both producer and retail prices to be integrated of order one I(1). Three structural breaks were found occurring in the years of 1996, 2002 and 2012. The Co-integration tests found that there is one long-run relationship between producer and retail prices. The Error Correction Model showed the return to a new equilibrium after a shock was 9% per month totalling over 11 months for a full recovery from a shock. The Granger (1988) Causality test indicated that producer prices do Granger cause retail prices in the short-run. In this study the latest econometric techniques were used including structural breaks which some previous studies overlooked. This study into the producer and retail prices in the UK pork industry is the latest study of this kind since the Brexit decision

Can black hole MACHO binaries be detected by the Brazilian spherical antenna?

Different studies show that dark matter of non-baryonic origin might exist. There have been experimental evidences that at least one form of dark matter has been detected through microlensing effects. This form of dark matter is named MACHOs (Massive Astrophysical Compact Halo Objects). The MACHO collaboration estimated that the masses of these objects are to be in the range 0.15-0.95 solar masses, where the most probable mass is of 0.5 solar masses. Some authors argue that MACHOs could be black holes, and that they could form binary systems, BHMACHO binaries. As is well known binary systems are sources of gravitational waves. The Brazilian spherical antenna will operate in the frequency band of 3.0-3.4 kHz, sensitive to binaries of a pair of 0.5 solar mass black holes just before coalescing. In the present work we study the detectability of these putative BHMACHO binaries by the Brazilian spherical antenna Mario Schenberg.Comment: 7 pages, 2 figure

Thermal connection and vibrational isolation: an elegant solution for two problems

Schenberg is a detector of gravitational waves resonant mass type, with a central frequency of operation of 3200 Hz. Transducers located on the surface of the resonating sphere, according to a distribution half-dodecahedron, are used to monitor a strain amplitude. To improve the performance of the detector it is essential to decrease the temperature, then it will be cooled down, this temperature could reach as low as 50 mK. This refrigerator produces vibration noise that could compromise the performance of Schenberg detector. In this work we the study such vibration noise and how it could be minimized proposing a new connection from the dilution refrigerator to the sphere suspension. The vibration attenuation is studied by finite element modeling (FEM) and an attenuation higher than 1024 is found, higher enough to note compromise the performance of Schenberg detector.Sao Paulo Federal Institute Rua Pedro Vicente 625, 01109-010 Sao Paulo, SP, BrazilFederal University of Sao Paulo, Department of Exact and Earth Sciences Rua Sao Nicolau 120, 09913-030 Diadema, SP, BrazilINPE Astrophysics Division, Sao Jose dos Campos, SP, 12227-010, BrazilFederal University of Sao Paulo, Department of Exact and Earth Sciences Rua Sao Nicolau 120, 09913-030 Diadema, SP, BrazilWeb of Scienc

Response of the Brazilian gravitational wave detector to signals from a black hole ringdown

It is assumed that a black hole can be disturbed in such a way that a ringdown gravitational wave would be generated. This ringdown waveform is well understood and is modelled as an exponentially damped sinusoid. In this work we use this kind of waveform to study the performance of the SCHENBERG gravitational wave detector. This first realistic simulation will help us to develop strategies for the signal analysis of this Brazilian detector. We calculated the signal-to-noise ratio as a function of frequency for the simulated signals and obtained results that show that SCHENBERG is expected to be sensitive enough to detect this kind of signal up to a distance of $\sim 20\mathrm{kpc}$.Comment: 5 pages, 4 figures, Amaldi 5 Conference Proceedings contribution. Submitted to Class. Quantum Gra