Something to say but not yet…

12/07/2017

Last week I have been in Montpellier to attend QCD 17 Conference hosted at the CNRS and whose mainly organizer is Stephan Narison. At this conference participates a lot of people from CERN presenting new results very nearly to the main summer conferences. This year, QCD 17 was in conjuction with EPSHEP 2017 were the new results coming from LHC were firstly presented. This means that the contents of the talks in the two conferences just superposed in a matter of few hours.

On Friday, the last day of conference, I posted the following twitter after attending the talk by Shunsuke Honda on behalf of ATLAS at QCD 17:

and the reason was this slide

The title of the talk was “Cross sections and couplings of the Higgs Boson from ATLAS”. As you can read from it, there is a deviation of about 2 sigmas from the Standard Model for the Higgs decaying to ZZ(4l) for VBF. Indeed, they can claim agreement yet but it is interesting anyway (maybe are we missing anything?). The previous day at EPSHEP 2017, Ruchi Gupta on behalf of ATLAS presented an identical talk with the title “Measurement of the Higgs boson couplings and properties in the diphoton, ZZ and WW decay channels using the ATLAS detector” and the slide was the following:

The result is still there but with a somewhat sober presentation. What does this mean? Presently, this amounts to very few. We are still within the Standard Model even if something seems to peep out. In order to claim a discovery, this effect should be seen with a lower error and at CMS too. The implications would be that there could be a more complex spectrum of the Higgs sector with a possible new understanding of naturalness if such a spectrum would not have a formal upper bound. People at CERN promised more data coming in the next weeks. Let us see what will happen to this small effect.


DICE 2014

21/09/2014

ResearchBlogging.org

I have spent this week in Castiglioncello participating to the Conference DICE 2014. This Conference is organized with a cadence of two years with the main efforts due to Thomas Elze.

Castello Pasquini a Castiglioncello sede di DICE 2014

Castello Pasquini at Castiglioncello  (DICE 2014)

I have been a participant to the 2006 edition where I gave a talk about decoherence and thermodynamic limit (see here and here). This is one of the main conferences where foundational questions can be discussed with the intervention of some of the major physicists. This year there have been 5 keynote lectures from famous researchers. The opening lecture was held by Tom Kibble, one of the founding fathers of the Higgs mechanism. I met him at the registration desk and I have had the luck of a handshake and a few words with him. It was a recollection of the epic of the Standard Model. The second notable lecturer was Mario Rasetti. Rasetti is working on the question of big data that is, the huge number of information that is currently exchanged on the web having the property to be difficult to be managed and not only for a matter of quantity. What Rasetti and his group showed is that topological field theory yields striking results when applied to such a case. An application to NMRI for the brain exemplified this in a blatant manner.

The third day there were the lectures by Avshalom Elitzur and Alain Connes, the Fields medallist. Elitzur is widely known for the concept of weak measurement that is a key idea of quantum optics. Connes presented his recent introduction of the quanta of geometry that should make happy loop quantum gravity researchers.Alain Connes at DICE2014 You can find the main concepts here. Connes explained how the question of the mass of the Higgs got fixed and said that, since his proposal for the geometry of the Standard Model, he was able to overcome all the setbacks that appeared on the way. This was just another one. From my side, his approach appears really interesting as the Brownian motion I introduced in quantum mechanics could be understood through the quanta of volumes that Connes and collaborators uncovered.

Gerard ‘t Hooft talked on Thursday. The question he exposed was about cellular automaton and quantum mechanics (see here). It is several years that ‘t Hoof t is looking for a classical substrate to quantum mechanics and this was also the point of other speakers at the Conference. Indeed, he has had some clashes with people working on quantum computation as ‘t Hooft, following his views, is somewhat sceptical about it.'t Hooft at DICE2014 I intervened on this question based on the theorem of Lieb and Simon, generally overlooked in such discussions, defending ‘t Hoof ideas and so, generating some fuss (see here and the discussion I have had with Peter Shor and Aram Harrow). Indeed, we finally stipulated that some configurations can evade Lieb and Simon theorem granting a quantum behaviour at macroscopic level.

This is my talk at DICE 2014 and was given the same day as that of  ‘t Hooft (he was there listening)My talk at DICE 2014. I was able to prove the existence of fractional powers of Brownian motion and presented new results with the derivation of the Dirac equation from a stochastic process.

The Conference was excellent and I really enjoyed it. I have to thank the organizers for the beautiful atmosphere and the really pleasant stay with a full immersion in wonderful science. All the speakers yielded stimulating and enjoyable talks. For my side, I will keep on working on foundational questions and look forward for the next edition.

Marco Frasca (2006). Thermodynamic Limit and Decoherence: Rigorous Results Journal of Physics: Conference Series 67 (2007) 012026 arXiv: quant-ph/0611024v1

Ali H. Chamseddine, Alain Connes, & Viatcheslav Mukhanov (2014). Quanta of Geometry arXiv arXiv: 1409.2471v3

Gerard ‘t Hooft (2014). The Cellular Automaton Interpretation of Quantum Mechanics. A View on the Quantum Nature of our Universe, Compulsory or Impossible? arXiv arXiv: 1405.1548v2


Some more news on warp drive

23/07/2013

ResearchBlogging.org

Today, New York Times published an article with an interview to Harold “Sonny” White about NASA studies on warp drive (see here). This revamped the interest about what NASA is funding (with a really small budget being  just $50,000) on this that have to be considered forefront research. For the readers that are not aware about what this research is aimed to, I invite them to read the very good article on Wikipedia about Alcubierre drive. As can be easily imagined, this article gets some new adding  each day and moves the curiosity of a myriad of people around the world. So, the activity of this NASA’s group is under a lot of attention by media and, with a lot of skepticism, by the scientific community. Alcubierre itself, the inventor of this idea, does not believe at all that is doable. The main reasons are well explained here (hat tip to Jennifer Ouellette) and one of these, the most important one maybe, is a lot of missing information as studies on this idea showed more its impossibility than else.

Anyhow,  we hope that Harold White will fill all the details at 2013 Starship Congress that he will attend giving a talk (see here). The schedule is here. He will speak on August 17th.

Miguel Alcubierre (2000). The warp drive: hyper-fast travel within general relativity Class.Quant.Grav.11:L73-L77,1994 arXiv: gr-qc/0009013v1


Return in Paris

15/06/2013

ResearchBlogging.org

After two years since the last edition, I was back in Paris to participate to the Twelfth Workshop on Non-perturbative Quantum Chromodynamics. The conference is organized by high-energy group at Brown University and held at Institut d’Astrophysique de ParisProfessor Chung-I Tan and Professor Berndt Mueller from Duke University are the organizers. As it also happened in the precedent edition, the workshop was really interesting and rich of ideas for research. The first talk was given by Kostantinos Orginos and was about nuclear physics emerging from lattice computations. The Sein (Paris)This is a matter that I am involved into as a “final user” and so, very near my interests. It is noteworthy to point out how current technology permits  to extract such results from lattice QCD making this a useful tool for the understanding of low-energy phenomenology. With Kostantinos,  his wife Vassiliki Panoussi and sons, we have had a nice social dinner on Tuesday night and I have had an interesting discussion about the current situation of lattice computations. The next speaker was Philippe de Forcrand that is well-known for his works on finite temperature QCD on the lattice.   He showed how the effective Yang-Mills theory at high temperature is surprisingly good with respect to lattice results also lowering temperatures at few times the critical temperature. Another interesting talk was the one by Peter Petreczy about the observables of QCD at finite temperature presenting also the most recent value for the critical temperature. As my readers may know, I computed this value in my recent paper on Physical Review C (see here) properly corrected by the mass gap of Yang-Mills theory. Norberto Scoccola and Daniel Gomez-Dumm showed similar results (see here).

On Tuesday it was the ultrarelativistic Heavy-ion collision session. This was particularly interesting and involved the talks of two friends of mine: Marco Ruggieri and Salvatore Plumari. In this area of research there is a really interesting and hot debated situation. On the other side, there is plenty of experimental results from RHIC and LHC. The session chair was Jean-Yves Ollitrault. He put the foundations to the current understanding of the quark-gluon plasma through a hydrodynamic approximation. What is observed in the experiments is the production of a flow of particles in a transverse direction named elliptic flow. Eiffel Tower (Paris)This is a clear evidence of existence for the quark-gluon plasma. Marco and Salvatore work in the group of Vincenzo Greco at University of Catania in Italy. The idea they based their work on is to derive the hydrodynamic equations from a kinetic description as the one provided by the Boltzmann equation. This approach opens up the scene to the possibility to derive such an equation and the full description of the quark-gluon plasma starting directly from QCD and fixing the collisional integral of the kinetic equation. Of course, one should understand the applicability conditions but my take is that, being the running coupling going to zero due to asymptotic freedom, a quark-gluon plasma should have scarce multi-collision effects. On the other side, this is a charged plasma but lives for a very small time. This means that this approach can prove to be really successful. One of the open questions is if, going at higher energies, a state called “color glass condensate” should form and this is a matter of a hot debate in the community. This is creating some tension that is reminiscent of the story I recounted about Landau gauge propagators for pure Yang-Mills theory (see here). A color glass condensate gives an increasing lower bound on the viscosity to entropy ratio by a factor 2 with respect to 1/4\pi, also computed from string theory, and appears less efficient with respect to observed elliptic flow at RHIC (see here). This kind of wars is often unproductive in physics and science at large as it slows down progress and good works could turn out unpublished. In situations like this, researchers should have eyes wide open and open minds granting all the contenders to be fairly listened waiting for experiments or careful lattice computations to say the last word. This should teach the history of Landau gauge propagators and also by looking back to history of physics. Otherwise we will stay on a silly forever war  where we are only able to prove to the rest of mankind that nothing has been learned from the past.

On Wednesday the session was dedicated to AdS/CFT, Holography, and Scattering. There was the talk of Carl Bender that is currently working on PT quantum mechanics. He is the pioneer of strong perturbation for quantum systems and quantum field theory. I often cited his work that has been a source of inspiration. David Dudal also spoke and discussed a holographic model for the analysis of strong ion collisions and the effect of the huge magnetic field generated. He gets results reminiscent of the Nambu-Jona-Lasinio model.  David is one of the proponents of the Refined Gribov-Zwanzinger model (see here). This is a real successful approach to the understanding of Landau gauge propagators and fits quite well with my results in the deep infrared behavior of a Yang-Mills theory as I also pointed out in my talk (see below).

On Thursday there was my talk in Paris. I will not comment about. On the morning, I heard the talk by Chung-I Tan, one of the organizers. He uses holographic techniques and the running coupling he obtains is similar to mine into an expansion in the inverse of the square root of the coupling. This is a nice result and it would be interesting to compare both of them numerically. One of the most interesting talks I heard was the one by Guy de Teramond. I have had reason to appreciate his work with Stanley Brodsky about holographic QCD and reduction to a Schrödinger-like equation to identify hadronic states (see here). With Guy I exchanged some interesting words and he was so kind to make compliments to my blog. A couple of talks were presented by cosmologists. The one by Patrick Peter about decoherence and cosmology struck me once again. I heard before about this matter and what makes me surprise is that the question of decoherence for a closed quantum system is stopped yet at the old Bohm pilot wave or a multiverse. Eiffel Tower SeesightThis should not be considered serious ways anymore because there is a theorem due to Barry Simon and Elliott Lieb, two giants of mathematical physics, that states that the limit of a large number of particles, in a reasonable many-body quantum system, reaches a Thomas-Fermi limit (see here where you can download a pdf). It is known that the Thomas-Fermi limit is just a semiclassical limit and the behavior of the matter is essentially classical. This means that one has not to recur to exotic hypothesis to understand what went on in the primordial universe and its fluctuations. I have recounted all this matter here. The final talk was given by Herbert Fried and was about a new understanding of dark matter and the universe using a new view of quantum electrodynamics.

It was a great workshop and I have been very happy to be there also this year. I hope people at Brown University will repeat this again. Thanks a lot!

Marco Frasca (2011). Chiral symmetry in the low-energy limit of QCD at finite temperature Phys. Rev. C 84, 055208 (2011) arXiv: 1105.5274v4

D. Gomez Dumm, & N. N. Scoccola (2004). Characteristics of the chiral phase transition in nonlocal quark models Phys.Rev. C72 (2005) 014909 arXiv: hep-ph/0410262v2

Ollitrault, J. (1992). Anisotropy as a signature of transverse collective flow Physical Review D, 46 (1), 229-245 DOI: 10.1103/PhysRevD.46.229

M. Ruggieri, F. Scardina, S. Plumari, & V. Greco (2013). Elliptic Flow from Nonequilibrium Color Glass Condensate Initial
Conditions arXiv arXiv: 1303.3178v1

David Dudal, John Gracey, Silvio Paolo Sorella, Nele Vandersickel, & Henri Verschelde (2008). A refinement of the Gribov-Zwanziger approach in the Landau gauge:
infrared propagators in harmony with the lattice results Phys.Rev.D78:065047,2008 arXiv: 0806.4348v2

Lieb, E., & Simon, B. (1973). Thomas-Fermi Theory Revisited Physical Review Letters, 31 (11), 681-683 DOI: 10.1103/PhysRevLett.31.681

Lieb, E., & Simon, B. (1977). The Thomas-Fermi theory of atoms, molecules and solids Advances in Mathematics, 23 (1), 22-116 DOI: 10.1016/0001-8708(77)90108-6

Marco Frasca (2006). Thermodynamic Limit and Decoherence: Rigorous Results Journal of Physics: Conference Series 67 (2007) 012026 arXiv: quant-ph/0611024v1


Higgs and beyond

06/06/2013

I am writing these few lines while the conference “Higgs and beyond” is still going on at Tohoku University (Sendai) in Japan. Talks can be found here. Both ATLAS and CMS presented a lot of results about Higgs particle and the most relevant of them is the combination of the data from the two experiments (see here). I am following the excellent recount by Richard Ruiz on twitter (@bravelittlemuon) that also takes care of CERN’s blog. Some interesting point is that there seems to be a bump in Z\gamma channel that is persistent also in other channels. About decay rates, improvements confirm yet nearly Standard Model behavior of the Higgs particle but with the rates of WW and ZZ going down with a too large error bars yet (see my preceding post).  Hopes are that CMS and ATLAS could combine also these data reducing error bars. No other Standard Model heavy Higgs particle is seen. Both CMS and ATLAS are looking for evidence of more Higgs particles to no avail yet. Of course, my view is that these excitations should be searched with somewhat different rates from Standard Model expectations. In any case, Standard Model confirms itself as one of the most successful theories in the history of physics. As said by one of ATLAS speakers: “There is overwhelming evidence for a new boson; there is overwhelming evidence for nothing else.” Both experiments plan to complete the analysis of data at 8 TeV for the summer conferences. My personal expectations are that just improvements in the precision of the measurements of the decay rates could eventually give hints of new physics. To fulfill other hopes, we need LHC upgrade that will restart operations on the spring of 2015, hopefully.


Fabiola Gianotti at Accademia dei Lincei

11/01/2013

On November 7th last year, Fabiola Gianotti, spokesperson of ATLAS experiment at CERN and one of the discoverers of the Higgs-like boson, has been nominated fellow of the Accademia dei Lincei. This is one of the oldest and most prestigious scientific societies that held fellows like Galileo Galilei and Enrico Fermi. Today, she held a public conference with fellows both of moral and scientific classes about “The Higgs boson and our life”. Fabiola Gianotti at Accademia dei Lincei Of course, I was there to see and listen to her personally. As I entered the room, I asked “excuse me” to three people blocking my passage to the chair. When I sat, I looked at them and I realized who were: Carlo di Castro, Francesco de Martini and Giovanni Jona-Lasinio. They were all my former professors. Also Giorgio Parisi was there and later Luciano Maiani entered the audience. Undoubtedly, the audience was truly remarkable.

Lamberto Maffei, president of the Accademia, introduced Gianotti through her main achievements and awards. I would like to remember that she gave the money of the Fundamental Physics Prize for student grants.

The aim of this conference was to convey to all fellows of the Accademia and public at large what was behind the discovery of the Higgs-like particle announced on July 4th last year. For me has been a good chance to hear, from one of the persons mastering this matter, a talk addressed to everybody without the use of technical jargon and using several nice images. Gianotti has shown a very fine gift for this. I would like to reassure my readers that she used comic sans.Fabiola Gianotti on TIME cover

By my side, I was proud to hear that 1400 scientists working at CERN are Italians and that an Italian company, Ansaldo Superconduttori Genova, is responsible for one third of the realization of the superconductors at LHC and are also installed in ATLAS detector. At CERN it is working  a great majority of young people. Gianotti said that it does not matter if you are a graduate student just entered the team. If your idea is good it is taken and applied. This is what makes scientific enterprise quite different from other realities and renders it so effective. Ideas count more than any authority.

Gianotti pointed out how difficult the situation is for Italy as we have a lot of young people leaving the country for academic positions at foreign universities while there are very few students coming in Italy to do research. Also, reduced budgets from our government with nonsensical cuts can produce a gap between generations of a line that produced excellent people. Recovering would be difficult then.

Turning attention to the discovery, I would like to emphasize that Gianotti repeated more and more times that the only certainty is that Standard Model, a beautiful theory, is verified with very high precision without no hint of breaking so far. But she warned the audience that we know that it must be overcome motivating this mostly from evidence of dark matter. The new particle, she said “Higgs-like”, resemble more and more the one originally postulated by Peter Higgs et al. but they have a lot of data to analyse yet and cannot be certain it is that one yet. They hope to clarify this matter with these other data (Moriond?).Fabiola Gianotti announces the new particle. She used an interesting image to describe the Higgs field to common people and then turned to the technical one to recover with respect to the formidable physicists were present there. Who speaks Italian can appreciate this video: Gianotti, Tonelli and Bertolucci explain Higgs field with children on similar lines.

The reason why she referred to our life is that most people generally ask “Why?”. Why all this effort to catch such a particle? She gave the beautiful example of J. J. Thompson and the discovery of the electron. When this happened both Thompson’s life and that of his neighbourhood did not change at all. But with the discovery of electronics and its application we all know now what all that has meant. For the Higgs particle can happen the same. From the discovery to its possible applications can pass some time and we need fundamental physics as a priori we cannot foresee the consequences but when they appear can be devastating and change our life definitely and forever for better. Gianotti said that without fundamental research, applied research dries up and eventually dies causing serious troubles to the economy of a country. I completely share her view. She also showed how hadron therapy and pet imaging were by-products of such endeavour.

Questions took more time than expected as the talk was really exciting and several people asked questions. She took this chance to recognize her debt with Ettore Fiorini, in the audience, that introduced her to particle physics and taught her a lot about it. Also Giorgio Salvini was present and asked for beyond LHC. Gianotti said that they hope to have LHC running for more than twenty years as also happened to other accelerator facilities. Salvini participated to most of the history of particle physics since Fermi’s time. He was in the experiment at CERN that produced W and Z particles for the first time with Carlo Rubbia. Francesco de Martini asked a technical question: Has Higgs particle cosmological implications? He was referring to a paper by Lee Smolin that claims that, due to this field, geometry should change from a Riemann to a Weyl one. Fabiola Gianotti and LHCGianotti answered immediately that the cosmological implications for the Higgs particle are enormous. The reason is that this is the first scalar particle ever discovered and inflation, the main mechanism in the Standard Model of cosmology to solve the problem of the homogeneity of the universe, has as a basic ingredient a scalar field. CERN discovery shows once again that the idea of inflation is in the right direction. de Martini was not satisfied with the answer turning back to the Smolin’s paper. Then Gianotti asked support to Giorgio Parisi, Parisi is one of the greatest Italian theoretical physicist, that confirmed Gianotti’s answer and said that, even if he is not an expert in the field of general relativity, people working in this research area have devised everything but the kitchen sink and so he would not be surprised if something like this was conceived.

In the end, a very beautiful talk from a great physicist. I would like to paraphrase what Gianotti said about Higgs and its light mass: Thanks Nature for giving us Gianotti!


Unbreakable

14/11/2012

Today, at HCP2012, new results on Higgs boson search were made available by CMS and ATLAS. Of course, well aligned with preceding rumors, all in all these appear rather disappointing. Maybe, beyond the increasing agreement with Standard Model expectations, the most delusional result is that the particle announced on July 4th appears to be completely lonely on a desert ranging till almost 1 TeV, at least if one is looking for other Higgs particles behaving Standard Model-like. \tau\tau decay rate is now aligning with expectations even if there is some room for a different outcome. On the other side, both experiments did not update \gamma\gamma findings. The scenario that is emerging from these results is the theorist’s nightmare. Tomorrow, all this will be collected in single talks by CMS and ATLAS speakers.

In a retrospective we could say that people claiming for a prize to discoverers of the Higgs mechanism seem to be vindicated. There appears no sign of supersymmetry that is more and more relinquished in a nowhere land. But, I would like to point out that, if a supersymmetric theory is the right one, there is just one theory to be singled out exploring the parameter space. It is normal in any case to see such a vast epidemic death of theories. It is also possible that theorists should now do a significant effort for new proposals beyond those largely explored in these last thirty years.

Standard Model is even more resembling a perfect theory really unbreakable and mimicking the success of the Maxwell equations put forward 150 years ago.  But we know it must break…

Finally, I would like to conclude this rather fizzling out post by pointing out a rather funny side of this situation. Tommaso Dorigo has a bet on with Gordon Watts and Jacques Distler amounting to $1200 on the non-existence of SUSY partners. This bet has not been payed yet as Distler is claiming there are a lot of “juicy rumors” from CERN and the terms are not fulfilled yet (see comments here).  I do not know what rumors Distler is talking about but, unless CERN is not hiding data (that would appear a rather strange behavior at best), maybe it is time to do a check on who the winner could be.


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