The Higgs boson and the Higgs field

 

The Higgs boson is the fundamental particle associated with the Higgs field. The Higgs boson was proposed in 1964 by Peter Higgs, François Englert, and four other theorists to explain why certain particles have mass. The Large Hadron Collider (LHC) at CERN in Switzerland has confirmed its existence in 2012 through the ATLAS and CMS experiments. 

The Standard Model predicts only massless particles, contradicting our experience. The solution was the Higgs boson, which can provide mass. The Higgs boson is the quantum excitation of the Higgs field. A key feature is that it takes less energy for the field to have a non-zero than a zero vacuum expectation value. This non-zero value could break electroweak symmetry, allowing the weak force bosons to acquire mass.

The consequences of the Higgs hypothesis:

1, Particles are massless. The Higgs boson lends mass by bumping into those massless particles. Mass would reduce the distance they can travel, which matches experimental findings. The field also explains the mass of other fundamental constituents, including electrons and quarks.

On the other hand, Einstein's general relativity tells us that mass is a permanent quality of particles. Mass can turn into energy by the equation. 

E = M C^2

If the mass is an acquired quality, then energy is also just a figment of the Higgs boson. 

2, In the months leading up to the discovery, the media was awash in buzz for the so-called "God" particle. The discovery of the Higgs boson was supposed to solve fundamental questions in physics about our world's structure. Nevertheless, five years after the discovery, the understanding of the physical world has not progressed. 

3, The Higgs boson with a mass of 125.35 GeV is too light to form a mass, giving interactions with other particles. To solve this problem, supersymmetry was born. Supersymmetry predicts the existence of extra particles, which would cancel out their Standard-Model partners' contributions to the Higgs mass, allowing a lighter mass Higgs boson. Thus, supersymmetry extends the Standard Model by predicting a super-partner particle for each known particle. These new particles, which could fix the Higgs boson's mass, seemed to explain the Higgs mass problem.

Unfortunately, no supersymmetric particles were observed in collisions at the LHC. Physicists are very clever can solve their problems. In the absence of supersymmetry, they proposed the existence of multiverses. According to this idea, the Higgs can take any mass. Each universe of the infinite number of universes would contain a specific mass Higgs particle. It's reasonable to assume that if there were an infinite number of universes, one of them might have a Higgs with the observed mass, and we are lucky to live in the universe with the right mass. 

Another proposed solution to solve the light-mass Higgs problem is yet another field, the axion field. The Higgs mass would depend on the hypothetical axion field's numerical value, which permeates space and time. Axions could relax the value of the Higgs mass to its observed value. 

4, The Higgs boson is a massive particle, around 125 GeV – that’s about 130 times the proton's mass at rest – with zero electric charges and spin. Where is Higgs boson mass coming from? It seems that the idea of the Higgs has only kicked the can down the road. What is your view, is there a Higgs boson or a Higgs hoax?  

Image credit: CERN for the ATLAS and CMS Collaborations

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Can the mind be examined as a physical system? Social consequences of the fermionic mind hypothesis

 

My latest work connects basic research in neuroscience with psychobiology, clinical diagnostic, and therapeutic insights. With my colleagues, we show how cognition balances sensory processing. 

Positive psychology recognizes the close relationship between social climate and resource availability. The social environment is an excellent determinant of the mindset of behavior in animals and people. In the late nineteenth century, the Russian scientist Peter Kropotkin found that species from bacteria and fish to mammals and birds lean toward generosity and cooperation when faced with abundance. From ants and bees to falcons, swallows, gazelles, and buffalos, as well as herds of wild horses, tribes of dogs, wolf packs, and communities of people form cooperation and generosity when faced with biological richness and supply abundance. Positive environments encourage generosity and cooperation by supporting security, trust, and confidence. Desirable population structures promote cooperation.

However, when the reduction of supplies reaches a tipping point, generosity disappears. Defections sweep through the population, the lack of resources inflicts a cognitive burden, which negatively affects IQ. The poor's lack of generosity originates in mental exhaustion rather than personality defects. The above considerations also might explain poverty’s role in negative personality transformations. Conspiracy theories, terrorism, and crime reflect the wide-spread distrust in governments, public institutions, and even science. We propose that the loss of a degree of freedom occurs through distrust. Therefore, interventions to provide basic social safety effectively raise the human race's overall cognitive performance.

Read the whole article in Computational and Structural Biotechnology Journal

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AlphaFold can predict the exact shape of proteins to precisions within the width of an atom.

 

Starting in the 1950s, the complete structures of proteins were determined by tedious laboratory experiments. Experimental techniques that can map out the structure of proteins in the lab, such as cryo-electron microscopy, nuclear magnetic resonance, and x-ray crystallography, can take hundreds of thousands of dollars and years of trial and error for each protein. 

  

A protein is a precise amino acid sequence that automatically folds itself up with many complex twists into a typical shape. The final structure determines how the protein behaves. Proteins' action is the key to the basic mechanisms of life, how we digest food, how hormones regulate behavior, and how our immune system fights disease. Efforts to develop vaccines for covid-19 have focused on the virus’s spike protein, for example. The way the coronavirus snags onto human cells depends on the shape of this protein and the shapes of the proteins on the outside of those cells. Therefore, finding the folded protein structures is an essential and vigorous research area.

The latest version of DeepMind’s deep-learning system, called AlphaFold, can find a protein’s shape in a few days with high accuracy. The new AlphaFold computational methods predicted the structure of dozens of proteins with a margin of error of just 1.6 angstroms—that’s 0.16 nanometers, less than the size of an atom. 

The breakthrough is a game-changer in pharmaceutical research, new drug design, and disease understanding. Many drugs are designed by simulating their 3D molecular structure, which requires knowing the structure of those proteins, which is true for only a quarter of the roughly 20,000 human proteins. AlphaFold will revolutionize this research. In the longer term, predicting protein structure will also help design synthetic proteins, such as enzymes that digest waste or produce biofuels. 

Read the whole article: Nature 588, 203-204 (2020)

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Essential Genes Evolve in Genome’s Junkyard

 

Essential genes are often thought to be frozen in evolutionary time-evolving only very slowly because their changing or elimination would lead to the organism's death. Hundreds of millions of years of evolution separate insects and mammals, but experiments show that the Hox genes guiding the development of the body plans in Drosophila fruit flies and mice can be swapped without a hitch because they are so similar. This remarkable evolutionary conservation is a foundational concept in genome research. But a new study turns this rationale for genetic conservation on its head. 

Rapidly changing heterochromatin drives the evolution of new essential genes. Young genes are just as likely as old ones to encode essential functions. The most rapidly evolving ones were much more likely to encode essential functions than the more slowly evolving ones. These transcription factors did not localize to euchromatin, the part of the genome where most genes are located, but in the heterochromatin — the regions of densely packed DNA that are mainly kept in a silent state because they contain most of the noncoding DNA and other so-called genomic junk.

Genes commonly evolve by duplication and divergence. A study examined the role of relatively abundant and functionally important de novo genes. These are newly evolved genes, without a possible parent gene. Under the right environmental conditions, stretches of DNA, without any function can provide some advantages, and thus start evolving under selection. Scientists found that overexpressing these proto-gene sequences enhanced growth, proving their potential for the evolution of new functions. 

The new insight could prove important in identifying genes relevant to various medical conditions and biological mysteries. Essential genes that are potential therapeutic targets can be hiding in the heterochromatin, hidden among genomic junk.

Read the whole article: Innovation of heterochromatin functions drives rapid evolution of essential ZAD-ZNF genes in Drosophila.

De novo emergence of adaptive membrane proteins from thymine-rich genomic sequences

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Sudden evolution of a more upright posture was spurred by warm-bloodedness: Posture shift at the end of the Permian, 252 million years ago.

 

During the Triassic, from 250 to 200 million years ago, the ancestors of both mammals and birds became warm-blooded at the same time. Life was recovering from the Permian-Triassic mass extinction, the greatest mass extinction of all time. It killed as much as 95 percent of life, and the very few survivors were repeatedly hit by global warming and ocean acidification. 

Warm bloodedness is an energy-requiring condition, but it permits the ability to compete better for resources and escape predators. Paleontologists identified warm-bloodedness and evidence for the early origin of feathers or hair in dinosaur and bird ancestors 250 million years ago. The origin of warm-bloodedness is connected to the exact time of the mass extinction. 

Several special features are linked to warm-bloodedness. One is the bones inside the nose and snout, called the turbinates. These bones increase the distance that air travels into the body, allowing it to warm up on the way in. There is also the bony palate, which separates the mouth from the nose and allows for continuous breathing, even while eating. Another, which is rarely preserved in the fossil records, is the presence of fur, which acts as an insulating layer.

At the same time, an almost instantaneous posture shift happened in mammal ancestors and bird ancestors. Amphibians and reptiles are sprawlers, holding their limbs partly sideways. Before the crisis, most reptiles had sprawling posture; afterward, they walked upright. This may have been the first sign of a new pace of life in the Triassic. In contrast, birds and mammals have erect postures, with the limbs immediately below their bodies. This allows them to run faster, and especially further. There are great advantages in erect posture and warm-bloodedness, but the cost is that endotherms have to eat much more than cold-blooded animals just to fuel their inner temperature control.

Read more about how our mammal ancestors became warm-blooded on Phys.org.

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Quantum entanglement between distant large objects

 

Entanglement is a link between two sister particles or objects, making them behave as a single entity. Researchers at the Niels Bohr Institute, University of Copenhagen, entangled a mechanical oscillator—a vibrating dielectric membrane—with an atom cloud's spin (magnetic orientation).  These very different entities were possible to entangle by connecting them with photons, particles of light. Atoms can be useful in processing quantum information, and the membrane—or mechanical quantum systems in general—can be useful for the storage of quantum information.

Professor Eugene Polzik, who led the effort, states that: "With this new technique, we are on route to pushing the boundaries of the possibilities of entanglement. The bigger the objects, the further apart they are, . . . the more interesting entanglement becomes from both fundamental and applied perspectives. With the new result, entanglement between very different objects has become possible."

The experiment might be a step towards limitless precision of measurements of motion.

The work, "Entanglement between distant macroscopic mechanical and spin systems" was published in Nature Physics.  

Read the whole article in Phys.org

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Quantum gravity: fact or fiction?

 

A new scientific paper suggests use interference of gravity waves to measure quantum gravity. Interference is a quantum phenomenon, where the combination of two or more electromagnetic waves to form a resultant wave, which is the sum of the original waves (i.e., bigger or smaller). 

In the experiment, laser light is shone on an electron. The electron can either absorb or not absorb the photon's energy. Absorbing the energy alters the electron's spin, either up or down. During quantum superposition, the electron spin is both up and down. Choosing an electron that is part of a large body, such as a diamond, the entire object—with a mass that is huge for quantum phenomena—would be in quantum superposition.

By applying a magnetic field, it is possible to separate the two quantum states. When these quantum states are brought together again by turning off the magnetic field, they will create an interference pattern. "The nature of this interference depends on the distance the two separate quantum states have traveled. And this can be used to measure gravity waves." These waves are contractions of space so that their passing affects the distance between the two separated states and thus the interference pattern. The apparatus can detect gravity waves. The scientists are hoping that entanglement between two large objects could be used to find out whether gravity itself is a quantum phenomenon. 

Entanglement is a quantum phenomenon. When two objects that interact only through gravity show entanglement, then gravity is also a quantum phenomenon. The experiment is a long shot with our current technology. Read more on the journal website.

Reference: 

Ryan J Marshman et al, Mesoscopic interference for metric and curvature & gravitational wave detection, New Journal of Physics (2020). DOI: 10.1088/1367-2630/ab9f6c

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