Hosted by Arijit Das, a PhD student. An overview of the Standard Model of Particle Physics.The Higgs was turning ten, and the World’s Largest Experiment would reboot in full steam after more than three years of enhancements. The mood was a celebration, motivating us to an enthralling discussion on the almost spotless theory: The standard model of particle physics. The discussion hosted by Arijit Das (PhD student, batch 21) set for the 2nd of July 2022 delved into the ideas behind quantum field theory; how particles were consequential of excitations of points on particular fields and the Casimir effect, wherein two plates move towards each other when kept pretty close. We briefly explored the ties to quantum properties like the electron's magnetic moment, the g factor, and internal degrees of freedom. With the bridge done, it was time to look at the turkey on the table, and no discussion of the standard model is ever complete without a biscuit with the Higgs Boson. The ever-expanding field engulfs all of us and gives most particles their mass. We also took a trip to the mathematically intriguing gauge symmetries and how Wu’s Experiment ridiculed us with the counter-intuitive idea that “Nature does not hold symmetry holy.” Ending on a high, we explored the questions that we cannot resort to the all-encompassing model for and how it has been the inception of an entire field of its own, understanding the world beyond the standard model and our quest for a unified theory of everything.

   PSIT will be starting our monthly screenings -we will be kicking off with an all time classic, "2001: A Space Odyssey". 2001: A Space Odyssey is a 1968 epic science fiction film produced and directed by Stanley Kubrick. The screenplay was written by Kubrick and science fiction author Arthur C. Clarke, and was inspired by Clarke's 1951 short story "The Sentinel" and other short stories by Clarke. The film stars Keir Dullea, Gary Lockwood, William Sylvester and Douglas Rain, and follows a voyage to Jupiter with the sentient supercomputer HAL after the discovery of an alien monolith.The film is noted for its scientifically accurate depiction of space flight, pioneering special effects, and ambiguous imagery.

   Hosted by Gouree and Eswar(B20). Friedmann equations, a set of equations that governs the universe expansion. The topic of discussion was the Friedmann equations - an important tool employed in the study of the field of cosmology. It was derived by Alexander Friedmann from Einstein’s field equations. At the time, it was dismissed as nothing more than “a mathematical curiosity” by the entire physics community, including Albert Einstein. This was because it suggested a model of the universe inconsistent with the static universe theory prevalent at that time. However, with further experiments, like those done by Edwin Hubble, it was confirmed that the universe was indeed expanding and so the Friedmann equations became the basic equations to describe the dynamics of the universe. The discussion mainly focused on introducing a few important concepts in cosmology - Hubble's law, redshift, cosmological principle, etc. as a prerequisite to understanding the topic. The derivation of the equation was done, in both nonrelativistic (Newtonian) and relativistic approaches. Further, the different fates of the universe as predicted by the Friedmann equations were also discussed.

   Hosted by Kartik Bhide(B17). We will look at the discovery of the Higgs Boson, from theory to experiment and beyond. 2012’s Nobel Prize for Physics was awarded for discovering the Higgs Boson and the mechanism by which Normal matter gets its mass. This was the topic of our discussion hosted by Kartik Bhide on the 4th of June 2022. We opened by discussing the significance of the discovery and the placement of the Higgs Boson in the Standard Model. The journey traversed to get the Higgs Boson involved a perfectly crafted soup of several fields of physics: Quantum mechanics, Special Relativity, Quantum Field Theory, and gauge symmetry. We dug in a bit more into the relations between rates of the collisions and the environment it ensues. When would one know whether our result fitted our theory? This question led to us discovering the minimum criterion for considering raw data turn to insightful observation. Concluding ideas saw the various detectors of the LHC and what’s in store for the future of its research.

PSI(T) launched its brand new talk series on electives, on the 1st of September, with the topic in discussion being Quantum Field Theory presented by Sharang R. Iyer, a fifth year BS-MS Student. Dr. Anil Shaji from School of Physics teaches this course.The essence of this theory is that it combines classical relativity and quantum mechanics. These are steps leading to the unified theory and the standard model. The problem of time in Schrodinger’s equation, negative energy solutions for relativistic wave equations, etc are studied. Other topics that are covered include quantum ideas involving states of various particles, classical field theory( which involves the math of vectors, tensors and spinors), Klein-Gordon Field and Dirac Field, quantizing and Feynman diagrams. Overall it was a fruitful discussion, which gave an insight into one of the electives provided here in IISER Thiruvananthapuram to students looking to major in physics

   We will primarily focus on Hubble tension and some mysteries behind an expanding universe. The Hubble’s Law, proposed by Edwin Hubble in collaboration with Georges Lemaître, is the observation in Cosmology that galaxies recede away from Earth’s respective at speeds proportional to their distance. The following equation represents it:



   Where v is the recessional velocity with which galaxies move away from Earth, d is the distance of these galaxies from the Earth, and Ho is the Hubble’s Constant (measured in kilometres per second per megaparsec). The initial value Hubble gave for Ho was around 500 km/s/Mpc, while more recent measurements place the value of Ho at about 70 Km/s/Mpc. The significant gap between the two values shows how much of an ordeal it is to measure the value of the Hubble Constant with precision — this is where the peer discussion kicked off, hosted by Vivek Kumar (BS-MS, Batch ‘19). We discussed the different methods used to find the value of Ho, including The European Space Agency’s Planck mission, which studied anisotropies of the Cosmic Microwave Background (CMB) to try and measure the global value of Ho, the Hubble Space Telescope’s study of type 1a supernovae, and the use of gravitational waves from binary neutron star mergers.
   The current accepted cosmological model is the ΛCDM (Lambda Cold Dark Matter) model, which accounts for the CMB, the large scale of celestial structures, and the universe's accelerated expansion. The Λ factor is responsible for the theorised existence of the infamous dark energy, which supposedly constitutes >69% of the total energy present in the universe. The early universe was stupendously hot and dense, but as it expanded, it slowly cooled down, got less dense, and became more ‘clumpy’ due to gravity. We get to determine the Hubble Constant (Ho) from the temperature fluctuations in the CMB and some other fancy factors that play essential roles in the ΛCDM model. The Planck Mission measured the value of Ho to be 67.31.2 Km/s/Mpc. Similarly, Vivek discussed the value measured by the Hubble Space Telescope, which studied red-shifts keeping Type 1a supernovae as the standard candles, as 73.24 1.74 Km/s/Mpc
   The discrepancies in the value of Ho arise due to the varying degree of cosmological models we assume beforehand. If there is an error in the model, it will also be reflected in the value of Ho. The ΛCDM may have slight optimisation issues (either computational or theoretical), thus giving inaccurate values of the Hubble Constant, or our observation methods need to be amended. The peer discussion ended with the possibility of our current accepted cosmological model – ΛCDM, to be a flawed description of the Universe and that another model needs to be made to try and understand the ever-increasing rapidity of the expansion of the Cosmos.

   Hosted by Aadi(B19). We will focus on the particle in a box problem, applications and insights on the same. The particle in a box is one of the first physical systems most students encounter while studying introductory quantum mechanics. The aim is to analyze the behaviour of an electron(neglecting the charge) in an infinite potential well by solving the Schrodinger equation, showing the differences between classical and quantum phenomena. Classically, we expect the particle to have a continuous range of energy values, as there is no constraint on the electron's momentum. In contrast, quantum mechanics predicts that a particle confined in such potential has a discrete energy spectrum, i.e. the electron can only have discrete energy values.
   To better account for the discrete energy of the electrons, one can represent them in k space, with the wave vectors in 3D being the coordinates of particles in this space. We find that the energy of a collection of electrons depends on the box's volume, suggesting that these electrons exert some pressure on the box walls. This pressure, known as electron degeneracy pressure, prevents the collapse of massive stars due to their gravity. This pressure can be accounted for in labs as a significant contributor to the bulk modulus of metals. The discussion was concluded with an interactive Q&A session which explored various concepts surrounding the PIB model.