The Reign of Bubbles and Particles

Published on by Catherine Toulsaly

The Reign of Bubbles and Particles

The legend says that since Portland’s founding, sightings of small green archers have been reported throughout downtown. Along with the archers, a celestial stag, a phantom building, and a huge tree have been spotted, time-to-time, throughout Old Portland.

The Green Man of Portland, Daniel Duford


A strange feeling washes over me when I travel from town to town. My body and mind seem bewildered as if they were trying to adjust to another universe. With its nonconformism, its Reedies gifted with an unusually independent mind, and its community credit unions and low-cost cinemas, Portland holds a special place in my memory. From the ‘little green men’ to the Green Man of Portland.

To think is difficult. To think about nothing is more difficult than about something.

Lev Okun



A few days after I wrote Universalis Cosmographia -- a post on data visualization --  the most comprehensive 3D mapping of the Universe from 300 000 years on was released. I’ll dig into it next. But first, because of my deep interest in topics such as ‘time before time’, nothingness, or the essence of ‘being’, I am using this post as an opportunity to read a bit about the growing and ever-more complex world of particles.  


The spread of information depends on the extent to which it is neither filtered, stopped nor altered as it bumps into the bubbles we, communities and individuals alike, live in.  My mind draws a parallel with the distant past and sets the stage of our preexistence. In a multiverse of bubbles only protected by the thickness of their walls, is our Universe bound to collapse or relatively stable? Lev Okun explained that what ‘primordial vacuum’ refers to is certain virtual states of particles



Turning to the multi-leveled stage of bubbles and elementary particles, from larger to smaller scales, could they too communicate with each other?  We paint a picture of their rise and fall. As our holobiont-like Universe enters infancy, its own army of bubbles burst, sending sound and gravitational waves. And when blisters of ionized hydrogen swell and start to proliferate and merge, they too are overshadowed by pockets of new stars and quasars which, themselves, interconnect.  


The Reign of Bubbles and Particles


A model of the Universe starts with a model of particles and works its way forward. I understand the concept of ‘superposition’ in the context of a universe of particles overlapping ours. Physicists have so far identified 57 species of elementary particles, but describe the number of hadrons -- which include mesons and baryons -- as limitless. Within the classification of mesons there are pions, while neutrons and protons are baryons.  Most of the baryons in the Universe are not found in stars, but rather they are in the form of a hot intracluster gas of hydrogen and helium.  A paper has just reported the direct measurement of the baryon content of the Universe. Hadrons are made of two or more quarks which come in six different flavors with their own mass --  up, down, top, bottom, charm, and strange. 


By studying charmed particles– particles containing charm quarks –, physicists can learn more about hadrons, in which quarks are bound by gluons, as well as the quark–gluon plasma which is thought to have existed in the early universe and can be recreated in heavy-ion collisions at the Large Hadron Collider (LHC).


In addition to a series of novel states consistent with containing four quarks that have been discovered in the past, the LHCb detector -- the single-arm forward spectrometer at the LHC -- has recently observed resonances interpreted to be pentaquark states. It is by sifting through the full LHCb datasets that a new particle structure was identified. It could originate from a hadron state consisting of four charm quarks but other interpretations cannot presently be ruled out. That said, not only there are hundreds of particles but theorists predict hypothetical ones such as sterile neutrinos, neutralinos, inflatons, majorons, and axions. 


 Xc1(3872) hadron (CERN)

Xc1(3872) hadron (CERN)

Particles’ inherent differences and multicombinations point to the distinctive character of their function and remind me of bees in a beehive. Defining their individual function is key to our understanding of fundamental questions such as those related to dark matter and the early Universe. How do all those particles get along? We know that the early universe was filled with hot plasma whose turbulence and related processes were induced by the presence of particles and by their collisions, but we still wonder how all the actors got involved and played their part in the formation of the Universe.  


The majority of a hadron’s mass actually comes from the energy of the gluons that bind quarks together but exactly how the energy of gluons translates to the mass of hadrons is a question physicists are still trying to answer.

Cesar Luis Da Silva

I see experiments in particle physics, in particular with the use of powerful particle colliders, as the backdrop for our never-ending stream of questions. Those experiments are a bit like a time machine whose goal is to reveal one new particle after another that may have taken part in the making of matter. Experiments highlight the process and timeframe of decay that not only depends on the mass of the particle but on the force that impacts them.  In doing so, they draw a picture of how it all happened although no one has ever observed a proton decay. The question lingers as to what other forms of matter and energy protons decay into. As we peel layers after layers, when will we reach the bottom layer? When will we say that this amounts to ‘nothingness’? Convinced that we will find a way, that we will build more advanced, more powerful instruments to see the unseen, we brush off the idea that nothingness exists.  

We tell the story of a hot Big Bang at millions of millions of degrees when gravity was not alone but together with the weak force, electromagnetism and the strong force that governs the dynamics of quarks and gluons. Magnetic fields originated at some point from the early universe and evolved as they interacted with the primordial plasma. Today we even contemplate the possibility that there may be a fifth force. Within the dynamics of bubble nucleation and growth, it is as much the frictional motion of the bubbles as they detonate and deflagrate as it is the interactions between particles in the plasma that matters. As the Universe expanded and cooled down, it underwent a series of phase transitions. A paper has proposed a hybrid model to probe the extraordinarily rapid and unstable conditions pertained to early-time dynamics and quark-gluon plasma.


As the color deconfined quark-gluon plasma cools below the critical temperature, it becomes energetically favorable to form color confined hadrons (primarily pions and a tiny amount of neutrons and protons due to the conserved net baryon number)

Michael B. Christiansen and Jes Madsen

During the quark-hadron transition, things cooled down even more in an area of roughly a thousand times the size of our Solar System where the quark-gluon was transformed into hadron gas. During the primordial nucleosynthesis, neutrons and protons combined to form the first nuclei. As the Universe kept on expanding and electrons interacted with photons, the cosmic microwave background was encoded with valuable information. 


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