Physics

This & this Reddit thread are nice places to start learning physics. I like reading AskPhysics subreddit.

I found studying Roger Penrose's work most fascinating.

Notes

• What is energy?
  • There's no satisfying definition beyond "the quantity that is conserved over time." This may sound arbitrary and ad hoc but it emerges from this deep mathematical principal called Noether's theorem that states that for each symmetry (in this case, staying the same while moving forward or backwards in time), there is something that is conserved. In this context, momentum is the thing that is conserved over distance, and angular momentum is the thing that is conserved through rotations.
  • The less rigorous explanation is that it's essentially the currency used by physical systems to undergo change.
• One of the things you learn in Physics is that nothing is ever still or completely solid. All atoms vibrate and most(95+%) of their space is empty, where electrons spin. So everything you see is a vibrating mesh of molecules. Neutrinos are so small they can fly straight through everything, even planets! The only time anything stays completely still is at zero degrees Kelvin and it is theorized that time actually stands still at the this temperature.
• Emergent complexity: complexity arising from simple rules is interesting. One example of it is cellular automata and Conway's game of life.
• Gravity travels at the speed of light.
• Acceleration is independent of mass of object.
• Inertia is an intrinsic property and can basically be described as a body’s resistance to acceleration/ change in it’s speed (1st law). What’s intertwined is inertia and force (not acceleration necessarily) since inertia (be it linear or rotational) of a particle would decide how much force is required to produce a certain acceleration (2nd law)
• The future is probability, the past is information, the passage of time is the collapse of one state to the other.
• Because atoms are actually 99.9999% (something similar to the degree) space, everything is also 99.9999% space but things cant pass through each other.
• All matter has kinetic and potential energy. It is easier to think of it as those are the only types of energy.
• Energy can change forms. From heat to potential to kinetic to radiation to heat.
• Gravity propagates at the speed of light.

Links

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• Ask HN: How to self-learn electronics?
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• Amazing Sand Pendulum
• Small physics lectures
• What in physics is fundamental?
• The World in UV
• Why does it take a million years for a photon moving at the speed of light to reach the sun's surface from its core?
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• The Feyman Lectures on Physics
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• A Child’s Guide to Spinors (2016)
• NIST Pair of Atomic Clocks Reveal Einstein's Relativity at a Personal Scale (2010) (HN)
• The Grand Design by Stephen Hawking
• Moonshot Papers (2020)
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• The Superpowers of Super-Thin Materials (2020) (HN)
• How Andrea Ghez won the Nobel for an experiment nobody thought would work (2020) (HN)
• Scientists find upper limit for the speed of sound (2020) (HN)
• Room-Temperature Superconductivity Achieved for the First Time (2020) (HN)
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• Crystallography
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• How does Hawking Radiation work? (2021)
• The Secret of Synchronization (2021)
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• This result could change physics forever (2021)
• Who are the current "rock stars" in physics? (2021)
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• Can We Understand the Standard Model Using Octonions? (Tweet)
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• Collection of Videos in Support of Geometric Unity (Reddit)
• David Tong: Lectures on Particle Physics (Reddit)
• The Map of Particle Physics | The Standard Model Explained (2021)
• Statistical mechanics from entanglement: The Eigenstate Thermalization Hypothesis (2021) (Reddit)
• Are all forces illusions? (2020)
• Intersection-free Rigid Body Dynamics (2021)
• Gravity is a double copy of other forces (2021) (HN)
• Lectures on Geometrical Anatomy of Theoretical Physics
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• Coanda Effect (2017)
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• Scattering Theory of Waves and Particles (1982)
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• Of the physicists that are still 'alive,' what is the top 5 of physicists who has contributed more to our understanding of the universe? (2021)
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• Does gravity bend gravity?
• Nanoscale and Quantum Photonics Lab
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• The Quantum Theory of Fields Book (2013)
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• Online Course: Machine Learning for Physicists 2020 (Code)
• An Analytical, Statistical Approximate Solution for Dissipative and non-Dissipative Binary-Single Stellar Encounters (2021) (HN) (HN)
• What is the Chandrasekhar Limit? (2021)
• The Planck scale: Is there a fundamental limit to space and time? (2020)
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• Physics of Racing
• How strong would a magnetic field have to be to kill you? (HN)
• Physics ∩ ML - Virtual hub at the interface of theoretical physics and deep learning.
• Physics-based Deep Learning (Paper)
• Why can’t I go faster than the speed of light? (2009) (HN)
• How can electrons be “topological”? (2020)
• Scientists Create Matter From Pure Light, Proving the Breit-Wheeler Effect (2021) (Reddit) (HN)
• Physics for Engineers and Scientists Book (2003)
• UC Berkeley: PHYS 10 - Physics for Future Presidents (2017)
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• What a solid made of electrons looks like (2021) (HN)
• What hidden symmetry is controlling the Universe? (2021)
• The Nobel Prize in Physics 2021- Physics for climate and other complex phenomena (HN) (Reddit) (Tweet)
• Atomic resolution video of salt crystals forming in real time (2021) (HN)
• Five Things We Still Don’t Know About Water (2015) (HN)
• Nature Physics (Twitter)
• MIT Introduction to Special Relativity (2021)
• What does it mean for light to be a wave? (2021)
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• Ultracold, superdense atoms become invisible (2021) (HN)
• Into the Cool: Energy Flow, Thermodynamics, and Life by Eric D. Schneider (2006)
• Gauss Linking Number and Electro-magnetic Uncertainty Principle (1997) (Tweet)
• Something Interesting about Albert Einstein’s Ph.D. Thesis
• Gravitation without the equivalence principle (2003)
• Gravitation without the equivalence principle (1957)
• Solver-in-the-Loop: Learning from Differentiable Physics to Interact with Iterative PDE-Solvers (2020) (Code)
• What Impossible Meant to Richard Feynman (2021) (HN)
• The Mystery of Snowflakes (2021)
• Gravitational waves should permanently distort space-time (2021) (HN)
• Oxford Physics Interview (2021)
• We all move at the Speed of Light (2018) (Reddit)
• The Year in Physics (2021) (Video)
• The Origins Of Constants Of Motion (2019)
• A delightful quirk of relativity theory (2022) (HN)
• The Joule-Thomson Effect and The Models We Know (2021)
• New lightweight material is stronger than steel (2022) (HN)
• Protons are probably smaller than long thought (2022) (HN)
• PDEs you should know (HN)
• How Einstein arrived at his theory of general relativity (HN)
• Why do electrons and protons have charge of exactly the same magnitude? (2022)
• What actually are electromagnetic waves? (2022)
• Главная надежда теоретической физики 21 века: Суперсимметрия (2022)
• Resources to self learn physics (2022)
• A deepening crisis forces physicists to rethink the structure of nature’s laws (2022) (HN)
• What is the most surprising thing we don't know (in physics)? (2022)
• Negative Temperature (HN)
• Nonlinear Dynamics: Concise Introduction Interlaced with Code (2022) (Code)
• Misconceptions that are common among physics students (2022)
• ELI5: Why is a Planck’s length the smallest possible distance?
• What I learned as a hired consultant to autodidact physicists (2016) (HN)
• Twenty-five years of nanoscale thermodynamics (2022) (Tweet)
• W boson mass may be 0.1% larger than predicted by the standard model (2022) (Reddit) (HN)
• Ludwig Boltzmann's inventions
• Faster-than-light communication - Wikipedia
• Collection of Database and Dataset Resources in Materials Science
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• It took me 10 years to understand entropy (2022) (HN)
• Did the W-boson just “break the standard model”? (2022) (HN)
• Nice resource for getting up to speed on physics (2022)
• Supersymmetry, explained visually (2022) (Reddit)
• A mind-blowing explanation of symmetry | Frank Wilczek (2022)
• The information-theoretic foundation of thermodynamic work extraction (2022) (Tweet)
• Ask HN: How to do self-study on Physics (2022)
• The Electromagnetic Spectrum - All the parts of the electromagnetic spectrum are the same thing—radiation. Radiation is made up of a stream of photons—particles without mass that move in a wave pattern all at the same speed, the speed of light.
• Jupyter notebook with steps to rediscover the Higgs boson yourself
• James Clerk Maxwell - A Sense of Wonder - Documentary
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• Lithium - Periodic Table of Videos (2016)
• preCICE - Coupling library for partitioned multi-physics simulations, including, but not restricted to fluid-structure interaction and conjugate heat transfer simulations. (Web)
• Ask HN: What is a nature of a magnetic field
• What would change if the speed of light was not constant in all reference frames
• Physicists discover a “family” of robust, superconducting graphene structures (2022) (HN)
• Deep Learning for Physics Research (Code)
• What is the holy grail in you field or area of research? (2022)
• Iris - Ultrafast electron scattering data exploration.
• Experimental protocol for testing the mass–energy–information equivalence principle (2022)
• The strength of the strong force (2022) (HN)