quarta-feira, 10 de abril de 2019

A game, now...

The Honourable Schoolboy



https://blackholehunter.org/

M87

The Honourable Schoolboy


Well, You may have already seen it zillion of times by now. Two comments if I may add: (i) it seems (Father) Albert got it again, scored, and GR passes another test; super applause for Einstein, GR rules the stage (so far); top notch and (ii) yes, contrary to the average reasoning about averaging, some people are truly U-N-I-Q-U-E and cannot be replaced, they are indispensable, to bring us to 'where' we are now. Rock on, Albert. Nb. If you got curious, see https://www.smithsonianchannel.com/shows/black-hole-hunters/0/3470276 Friday, April 12 at 9 PM ET/PT on Smithsonian Channel. 

segunda-feira, 25 de março de 2019

I wish....and hey, that it is my boat. The single mast. I am moving...

The Honourable Schoolboy


Beyond the event horizon and loneliness...

The Honourable Schoolboy









At the gravity and cosmology group site, at this Science Festival week (https://www.maths.cam.ac.uk/events/hands-maths-fair-cambridge-science-festival), I had an experience that has made me think and kept thinking.

There was a display of gravitational lensing simulation and a child approach, to see what was all about (their parents and brother were nearby seeing a hollow table with a towel, bent with masses to simulate the space time curvature, wooden and metal spheres to represent planets moving… ; you know the drill…) . From the conversation, we went to black holes being a possible source for such lensing effect. And then it became interesting.

The child asked if the Earth could be inside a black hole. Sort of “swallowed”; ‘Well, yes...’. To my surprise, this meant… relief to the child. ‘So, everybody will be there, all things’ (that were or are on Earth); ‘Well, yes...’ [I should have told about the tidal forces and ‘spaghetization’, horizon crossing, singularity … but refrain from that. The child got me really curious, what has the line of reasoning? I guess hearing a math tutor say at the start that “we should look more to question their answers rather than answer their questions (the children’s)” was driving my attention and listening]. ‘So, all our friends, everybody will be with you, all things there?’; ‘Well, yes...’ (I was not sure if I should become more technical and possibly say something that would be unfortunate). Then the child said (to my utter surprise and I still think of it) ‘we will not be alone in the black hole. It will be fine, it is also infinite there, everything will be there’. I was glued to the ground. The child had also seen the posters, one was about Hawking’s site in Westminster, the one with the black hole citation. So, the child was enquiring about black holes, but also about loneliness, no one there if we go into there, or everybody there, but it was infinite as the whole Earth (and what we see and know) could be there, so that will be fine, then. Maybe I am making a wrong interpretation but I found this fascinating. The child should be about 8 years old, I think. Maybe a bit more? But already knowing about black holes, what they could cause, their existence, their effects, loneliness…, a notion of infinity being about all one could know or have or see, not really a scale of the whole universe but what could be seen and know on earth and from it. Then it make think further: if all the memories and all experiences go into the black hole, even if there is evaporation and all that (I did not mention this to the child, because I did not want to bring the idea that memories or someone\thing could be lost from the Earth in the black hole…and the relief will be eliminated), there is the loss of information paradox at black holes, so... our existence and memories and legacy(ies) will be possibly lost, scattered? What’s the meaning of this or that.... It made me think a bit more on that ‘(hyper)surface’. It was really a learning moment for me: at the child age, I was possibly hearing the Beatles, ‘yellow submarine’, world cup of 66 or 70 or maybe not that but other things, but no way I was aware of the black hole concept, their effects, loneliness, infinity, … So the children of today, that do make these questions, have from school, tv, science outreach, cinema, internet and games, a very rich perspective, will go and study black holes and other stuff, presumably solve the loss of information paradox (https://en.wikipedia.org/wiki/Black_hole_information_paradox) being motivated by … their early age memories, feelings of being lonely ‘there’ (or not), what about one’s friends and things, will all be together, eternity, memories…


Still thinking of it. First thing I did this Monday morning was to order the 50p coin https://www.royalmint.com/our-coins/events/stephen-hawking/celebrating-the-life-of-stephen-hawking-2019-uk-50p-brilliant-uncirculated-coin/?gclid=CjwKCAjw-OHkBRBkEiwAoOZql9Mz5NONB1HWrG3UQLqMBRhcE_2n_0LLRB4QZxacBBcfLO3cbRCJwhoCgKIQAvD_BwE.




terça-feira, 12 de março de 2019

sexta-feira, 22 de fevereiro de 2019

...

https://expresso.sapo.pt/sociedade/2019-02-22-OCDE-diz-que-Portugal-tem-de-formar-doutorados-para-trabalharem-nas-empresas

quinta-feira, 21 de fevereiro de 2019

quarta-feira, 6 de fevereiro de 2019

Kinetic inflation in deformed phase space Brans–Dicke cosmolog

The Honourable Schoolboy

https://www.sciencedirect.com/science/article/pii/S2212686419300184?dgcid=rss_sd_all

Kinetic inflation in deformed phase space Brans–Dicke cosmology

J.MartoabP.V.Monizabc
a
Departamento de Física, Universidade da Beira Interior, Rua Marquês d’Avila e Bolama, 6200-001 Covilhã, Portugal
b
Centro de Matemática e Aplicações (CMA - UBI), Universidade da Beira Interior, Rua Marquês d’Avila e Bolama, 6200-001 Covilhã, Portugal
c
DAMTP, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK
Received 24 May 2018, Revised 23 December 2018, Accepted 16 January 2019, Available online 5 February 2019.

Abstract

In this paper, by establishing a Brans–Dicke (BD) cosmology by means of a deformed phase space, in the absence of any scalar potential, cosmological constant and ordinary matter, we show that it is feasible to overcome obstacles reported in the corresponding commutative (non-deformed) frameworks. More concretely, by applying the Hamiltonian formalism and introducing a dynamical deformation, between the momenta associated to the FLRW scale factor and the BD scalar field, we obtain the modified equations of motion. In particular, these equations reduce to their standard counterparts when the noncommutative (NC) parameter is switched off. By focusing on a specific branch of solutions, in contrast to standard frameworks (even with a varying BD coupling parameter), we show that we can obtain an adequate appropriate inflationary epoch possessing a suitable graceful exit. In other words, in the Jordan frame (JF), such branch of solutions properly satisfy the sufficient condition required for satisfactory inflation, which is equivalent to get an inflationary phase in the conformal Einstein frame (EF) without branch change. Concerning the cosmological dynamics, we further show that our NC framework bears close resemblance to the
(Starobinsky) inflationary model.

Keywords

Inflation
Noncommutativity
Brans–Dicke theory


Cover image Physics of the Dark Universe