/Physics_Stuff

Physics you have some explanation to do.

Notions ( in no order ):

  • CCC theory ( Conformal Cyclic Cosmology ): In Roger Perose's CCC, the universe iterates through infinite cycles, with the future timelike infinity of each previous iteration being identified with the Big Bang singularity of the next. Penrose popularized this theory in his 2010 book Cycles of Time: An Extraordinary New View of the Universe.
  • Local hidden-variable theory: in the interpretation of quantum mechanics is a hidden-variable theory that has the added requirement of being consistent with local realism. It essentially explains that un-locality does not exist and can be explained by a hidden variable ( IE the measurment would be predictable if we knew that hidden variable )
  • Bell's theorem: Bell's theorem proves that quantum physics is incompatible with local hidden-variable theories. It was introduced by physicist John Stewart Bell in a 1964 paper titled "On the Einstein Podolsky Rosen Paradox", referring to a 1935 thought experiment that Albert Einstein, Boris Podolsky and Nathan Rosen used in order to argue that quantum physics is an "incomplete" theory.
  • Brewster's angle: Brewster's angle is an angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with no reflection. When unpolarized light is incident at this angle, the light that is reflected from the surface is therefore perfectly polarized.
  • Stern–Gerlach experiment: experiment demonstrated that the spatial orientation of angular momentum is quantized. Thus an atomic-scale system was shown to have intrinsically quantum properties. In the original experiment, silver atoms were sent through a spatially varying magnetic field, which deflected them before they struck a detector screen, such as a glass slide.
  • Squeezed Vacuum: Quantum squeezed states are a consequence of uncertainty relations; a state is squeezed when the noise in one variable is reduced below the symmetric limit at the expense of the increased noise in the conjugate variable such that the Heisenberg uncertainty relation is not violated.
  • parametric down-conversion: Spontaneous parametric down-conversion (also known as SPDC, parametric fluorescence or parametric scattering) is a nonlinear instant optical process that converts one photon of higher energy (namely, a pump photon), into a pair of photons (namely, a signal photon, and an idler photon) of lower energy.
  • Two-photon emission: It's a better, mor efficient alternative to the BBO crystal mechanism of parametric down-conversion. >> Observation of two-photon emission from semiconductors
  • Positron Catalysed Nuclear Fusion: decay of a radio-active material produces pairs of positron-electrons, which using a magnetic field and an array of coolers ( to reduce the speed of hot postrons ) postrons will be redirected to a reactor to catalyze the mechanism, PostronDynamics's working on this as a means of propulsion.
  • The Chinese Room Argument: It argues agains Alan Turing prediction where if a computer can convince a human that it's a human. it says that if you put a person who doesn't understand Chinese in a room with an instruction book / dictionary, then he receives a message in Chinese and responds using instructions, that doesn't make him Chinese or undrestand it.
  • Cherenkov radiation: Cherenkov radiation is electromagnetic radiation emitted when a charged particle passes through a dielectric medium at a speed greater than the group velocity of light in that medium. A classic example of Cherenkov radiation is the characteristic blue glow of an underwater nuclear reactor. but it's also used to detect Neutrinos in Super Kamiokande observation for instance.
  • MOND: (Modified Newtonian dynamics) Modified Newtonian dynamics is a hypothesis that proposes a modification of Newton's law of universal gravitation to account for observed properties of galaxies.
  • Chirp cooling: (or Laser-Cooling or Zeeman Cooling) is the method of using the photon momentums to slow atoms down ( cooling them ) from an atom beam with an opposite direction to near absolute zero in a region of space.
  • Doppler cooling: in this method we essentially use the doppler effect and a bunch of lasers from different directions with an off-resonant lower frequency than the atoms to trap them in-place and taking the motion (heat) out of them.
  • Zeeman effect: The Zeeman effect is the effect of splitting of a spectral line into several components in the presence of a static magnetic field. It is named after the Dutch physicist Pieter Zeeman, who discovered it in 1896 and received a Nobel prize for this discovery.
  • Stark effect: The Stark effect is the shifting and splitting of spectral lines of atoms and molecules due to the presence of an external electric field. It is the electric-field analogue of the Zeeman effect.
  • Objective-collapse theory: or Objective reduction, Objective-collapse theories, also known as models of spontaneous wave function collapse or dynamical reduction models,[1][2] were formulated as a response to the measurement problem in quantum mechanics,[3] to explain why and how quantum measurements always give definite outcomes, not a superposition of them as predicted by the Schrödinger equation, and more generally how the classical world emerges from quantum theory. The fundamental idea is that the unitary evolution of the wave function describing the state of a quantum system is approximate. It works well for microscopic systems, but progressively loses its validity when the mass / complexity of the system increases.
  • Equivalence principle: fundamental law of physics that states that gravitational and inertial forces are of a similar nature and often indistinguishable, originally stated by Galileo. In Einstein’s version, the principle asserts that in free-fall the effect of gravity is totally abolished in all possible experiments and general relativity reduces to special relativity, as in the inertial state.
  • Energy-Frequency equivalence Max Planck equation E = hc/λ.
  • Mass–energy equivalence Einstein's famous Equasion E = mc^2.
  • Copernican principle: In physical cosmology, the Copernican principle states that humans, on the Earth or in the Solar System, are not privileged observers of the universe. Named for Copernican heliocentrism, it is a working assumption that arises from a modified cosmological extension of Copernicus's argument of a moving Earth.
  • Anthropic Argument Anthropic principle, is the principle that there is a restrictive lower bound on how statistically probable our observations of the universe are, given that we could only exist in the particular type of universe capable of developing and sustaining sentient life.
  • Bloch's theorem: In condensed matter physics, Bloch's theorem states that solutions to the Schrödinger equation in a periodic potential take the form of a plane wave modulated by a periodic function.
  • Gauge theory: a type of field theory in which the Lagrangian (and hence the dynamics of the system itself) does not change (is invariant) under local transformations according to certain smooth families of operations (Lie groups).
  • Newotonian Formalism: Finds out and formulates, all the forces, how, when and where a transformation happens. become very complicated for complex motions.
  • Lagrangian Formalism: In short: The path that took the least action was taken! does not matter how, and when and where. generalizing and simplifying equasion.
  • Hamiltonian Formalism: a formulation of classical mechanics and is founded on the stationary action principle. (shrodinger equasion is Hamiltonian)
  • Beer–Lambert law: in optics, the empirical relationship of the absorption of light to the properties of the material through which the light is traveling.
  • Bragg's law: the angles for coherent and incoherent scattering from a crystal lattice.
  • Brewster's law: an angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with no reflection. Named after Scottish physicist David Brewster.
  • Eötvös effect: Because of the rotation of earth, a train ( for instance ) going against the rotation of earth will weight more ( as it feels less centrofugal force ) and vice versa.
  • Elitzur–Vaidman bomb tester: The Elitzur–Vaidman bomb-tester is a quantum mechanics thought experiment that uses interaction-free measurements to verify that a bomb is functional without having to detonate it. It was conceived in 1993 by Avshalom Elitzur and Lev Vaidman.
  • Mach–Zehnder interferometer: a device used to determine the relative phase shift variations between two collimated beams derived by splitting light from a single source. The interferometer has been used, among other things, to measure phase shifts between the two beams caused by a sample or a change in length of one of the paths.
  • Fermi Paradox: there should be life elsewhere in the universe, but we haven't found any evidence of it so far.
  • Dark Forest: is a soltion to Fermi Paradox that sais that we don't see any evidence because any civilization who presented a sign, caused alien predators to hunt and destroy them, hence only those who are good at hiding remain!
  • Region of Potential Simultaneity: a region of space around an event where the seed of causality can not reach, hence the events in this region are neither earlier or later than the main event.
  • Boltzman theory: Boltzman suggested that ina sufficiently large and old universe, there ought to be regions, where time goes backward ( entropy )
  • josephson junction: In Physics, the Josephson effect is a phenomenon that occurs when two superconductors are placed in proximity, with some barrier or restriction between them. where they allow current to flow through the gap on both directions ( due to quantum tunnelling ) without any voltage applied! this is used to create super-position of current and magnetic fields.
  • S.Q.U.I.D: Or Superconducting Quantum Interference Device, is an arrangment of Josephson Junctions that allows for extremely sensitive measurments of subtle magnetic fields.
  • SERF: Or spin exchange relaxation-free (SERF) magnetometer is a type of magnetometer developed at Princeton University in the early 2000s. SERF magnetometers measure magnetic fields by using lasers to detect the interaction between alkali metal atoms in a vapor and the magnetic field. These are potentially more sensitive than SQUIDs and do not require cryogenic refrigeration but are orders of magnitude larger in size (~1 cm3) and must be operated in a near-zero magnetic field.
  • Penning Trap: is a device for the storage of charged particles using a homogeneous axial magnetic field and an inhomogeneous quadrupole electric field. this device is specially very useful in storing things that are impossible to contain like Anti-matter which will anihilate when comes in contact with normal matter.
  • Weak Equivalence Principle: (WEP) states that all point-like structureless particles fall along the same path within a gravitational field. If general relativity is correct, the WEP holds for all forms of matter and antimatter.
  • hund principle: Every subshell in each orbital level is occupied bya single electron before any of them accept the second one.
  • Wigner crystal: A gas of electrons moving in 2D or 3D in a uniform, inert, neutralizing background will crystallize and form a lattice if the electron density is less than a critical value.
  • Magneto-rotons: are elementary excitations at finite momentum that appear in gases of interacting charged particles placed under a strong magnetic field.
  • Kelvin–Helmholtz instability: The Kelvin–Helmholtz instability (after Lord Kelvin and Hermann von Helmholtz) is a fluid instability that occurs when there is velocity shear in a single continuous fluid or a velocity difference across the interface between two fluids.
  • Mach's principle: The hypothesis attempted to explain how rotating objects, such as gyroscopes and spinning celestial bodies, maintain a frame of reference. in other words if instead of the rotating object, the whole universe started to rotate around the object, it would feel the same cetrefugal force! This of course could be wrong and is not proven or disproven.
  • Frame-dragging: (also called the Lense–Thirring effect for rotational frame-dragging) The effect of the rotation of a massive body on the space-time field around it. This was confirmed at 2011 from the data that was provided by a NASA satelite sent to orbit for this reason. ( for earth it was 0.000011 degree per year ). Qualitatively, frame-dragging can be viewed as the gravitational analog of electromagnetic induction.
  • van der Waals forces: relatively weak electric forces that attract neutral molecules to one another in gases, in liquefied and solidified gases, and in almost all organic liquids and solids.
  • The spin Hall effect of light (SHEL): is the photonic analogue of the spin Hall effect in electronic systems, in which the electron spin and role of an applied electric field are replaced by the polarization of an incident light wave and the refractive index gradient of the sample material, respectively.
  • Tsirelson's bound: is an upper limit to quantum mechanical correlations between distant events. Given that quantum mechanics violates Bell inequalities (i.e., it cannot be described by a local hidden-variable theory), a natural question to ask is how large can the violation be. In general, this bound is lower than the bound that would be obtained if more general theories, only constrained by "no-signalling" were considered. ( 85% vs 75% for local hidden vars )
  • CHSH inequality: the CHSH inequality can be used in the proof of Bell's theorem, which states that certain consequences of entanglement in quantum mechanics can not be reproduced by local hidden-variable theories. Experimental verification of violation of the inequalities is seen as experimental confirmation that nature cannot be described by local hidden-variables theories. CHSH stands for John Clauser, Michael Horne, Abner Shimony, and Richard Holt, who described it in a much-cited paper published in 1969.

QM interpretations short list:

  • Copenhagen interpretation: The Copenhagen interpretation is a collection of views about the meaning of quantum mechanics principally attributed to Niels Bohr and Werner Heisenberg. It is one of the oldest attitudes towards quantum mechanics, as features of it date to the development of quantum mechanics during 1925–1927, and it remains one of the most commonly taught. There is no definitive historical statement of what is the Copenhagen interpretation, and there were in particular fundamental disagreements between the views of Bohr and Heisenberg. but in general it states that nature is intrinsically probabilistic, and that particles actually don't have properties such as position or momentum until they are observed.
  • Many worlds: The many-worlds interpretation is an interpretation of quantum mechanics in which a universal wavefunction obeys the same deterministic, reversible laws at all times; in particular there is no (indeterministic and irreversible) wavefunction collapse associated with measurement. The phenomena associated with measurement are claimed to be explained by decoherence, which occurs when states interact with the environment. More precisely, the parts of the wavefunction describing observers become increasingly entangled with the parts of the wavefunction describing their experiments. Although all possible outcomes of experiments continue to lie in the wavefunction's support, the times at which they become correlated with observers effectively "split" the universe into mutually unobservable alternate histories.
  • Objective collapse: Objective collapse theories differ from the Copenhagen interpretation by regarding both the wave function and the process of collapse as ontologically objective (meaning these exist and occur independent of the observer). In objective theories, collapse occurs either randomly ("spontaneous localization") or when some physical threshold is reached, with observers having no special role. Thus, objective-collapse theories are realistic, indeterministic, no-hidden-variables theories. some of the theories in this group include:
    • Penrose interpretation.
    • the Ghirardi–Rimini–Weber theory
    • the continuous spontaneous localization model
  • Retro-Causality: or Time-symmetric theories. These theories address the non-localatity issue and faster than the speed of light communication problem by proposing that the information is transfered backward in time and not simultaniously! one famous theory is Transactional interpretation theory.
  • QBism or Quantum Bayesianism: It essentially says that wave function doesn't collapse in real world, but in our bielief system!
  • Pilot wave theory or De Broglie–Bohm theory or Bohmian Mechanics, says that universe is completely deterministic. Particles, which always have positions, are guided by the wavefunction. The wavefunction evolves according to the Schrödinger wave equation, and the wavefunction never collapses. The theory takes place in a single spacetime, is non-local, and is deterministic. The simultaneous determination of a particle's position and velocity is subject to the usual uncertainty principle constraint. The theory is considered to be a hidden-variable theory, and by embracing non-locality it satisfies Bell's inequality. The measurement problem is resolved, since the particles have definite positions at all times.Collapse is explained as phenomenological.
  • Relational Quantum Mechanics: Different observers from different frames of reference can observe different versions of collapse of wave function.
  • Quantum information theories: The state is not an objective property of an individual system but is that information, obtained from a knowledge of how a system was prepared, which can be used for making predictions about future measurements. ...A quantum mechanical state being a summary of the observer's information about an individual physical system changes both by dynamical laws, and whenever the observer acquires new information about the system through the process of measurement.
  • more ..

#Laws of Thermodynamics: 0. Zeroth law: If two systems are both in thermal equilibrium with a third system, then they are in thermal equilibrium with each other.

  1. First law: In a closed system, the first law states that the change in internal energy of the system is equal to the difference between the heat supplied to the system and the work done by the system on its surroundings.
  2. Second law: (by Nicolas Léonard Sadi Carnot, French physicist) When two initially isolated systems in separate but nearby regions of space, each in thermodynamic equilibrium with itself but not necessarily with each other, are then allowed to interact, they will eventually reach a mutual thermodynamic equilibrium. The sum of the entropies of the initially isolated systems is less than or equal to the total entropy of the final combination. Equality occurs just when the two original systems have all their respective intensive variables (temperature, pressure) equal; then the final system also has the same values.
  3. Third law: A system's entropy approaches a constant value as its temperature approaches absolute zero.

Other ( more philosophical ) notions:

  • God Of Gaps: is a theological perspective in which gaps in scientific knowledge are taken to be evidence or proof of God's existence.
  • Noblesse oblige: Based on Schrödinger it means you should not talk about topics that you are not an expert in ( not sure if that's what it means tho! and I'm not an expert in it!! )
  • Single-event upset: when high energy particles change a bit in our digital devices ( like the super-mario jump that happened in 2013 or 1979, when Ziegler from IBM and Lanford from Yale for the 1st time described the process and added shielding to ICs, that the same year world’s first heavy ion “single event effects” test at a particle accelerator facility, conducted at Lawrence Berkeley National Laboratory's 88-Inch Cyclotron and Bevatron. or the Quantas airline flight incident )
  • Goodstein's theorem: n mathematical logic, Goodstein's theorem is a statement about the natural numbers, proved by Reuben Goodstein in 1944, which states that every Goodstein sequence eventually terminates at 0. Kirby and Paris[1] showed that it is unprovable in Peano arithmetic (but it can be proven in stronger systems, such as second-order arithmetic).
  • Orch OR: Orchestrated objective reduction, is a controversial hypothesis that postulates that consciousness originates at the quantum level inside neurons, rather than the conventional view that it is a product of connections between neurons. The mechanism is held to be a quantum process called objective reduction that is orchestrated by cellular structures called microtubules. It is proposed that the theory may answer the hard problem of consciousness and provide a mechanism for free will. --> In Orch-Or the Orch is for Orchestration and Or is for Organization.
  • kernel theorem: In mathematics, the Schwartz kernel theorem is a foundational result in the theory of generalized functions, published by Laurent Schwartz in 1952. It states, in broad terms, that the generalized functions introduced by Schwartz (Schwartz distributions) have a two-variable theory that includes all reasonable bilinear forms on the space {\displaystyle {\mathcal {D}}}{\mathcal {D}} of test functions. The space {\displaystyle {\mathcal {D}}}{\mathcal {D}} itself consists of smooth functions of compact support.
  • Goldbach's conjecture: One of the oldest and best-known unsolved problems in number theory and all of mathematics. It states that every even whole number greater than 2 is the sum of two prime numbers.
  • Penrose Consciousness: Roger penrose have said that he sees 3 parts in Consciousness: intelligence understanding and awareness.
  • Occam's razor: Occam's razor, Ockham's razor, Ocham's razor (Latin: novacula Occami), also known as the principle of parsimony or the law of parsimony (Latin: lex parsimoniae), is the problem-solving principle that "entities should not be multiplied beyond necessity",[1][2] sometimes inaccurately paraphrased as "the simplest explanation is usually the best one.
  • Being Anti Copernican, hints at the notion that at the time of Copernicus, Galileo's ideas was rejected because one could not feel the earth moving.
  • Babinet's principle: the diffraction pattern from an opaque body is identical to that from a hole of the same size and shape except for the overall forward beam intensity. also on the far field, you'll lose twice as much light energy as you'd expect ( absorbed + edge scattered )
  • Bayes' theorem: describes the probability of an event, based on prior knowledge of conditions that might be related to the event.
  • Benford's law: In many collections of data, a given data point has roughly a 30% chance of starting with the digit 1.
  • Briffault's law: The female, not the male, determines all the conditions of the animal family. Where the female can derive no benefit from association with the male, no such association takes place.
  • Buys Ballot's law: is concerned with the notion that the wind travels counterclockwise around low pressure zones in the Northern Hemisphere.
  • Gravitational Redshift: the time ticks at different rates depending on how close to a massive space-time bending object (Like earth) they are
  • Einstein–de Haas experiment: the experiment that demonstrate the angular momentum assigned to the electron's spin.
  • Gedankenexperiments: german for thought experiment

Random notes:

Components of consciousness:

  • sensing the environment
  • awareness of environment (food and threats).
  • perception ( like vision )
  • desire
  • Remembering
  • Object permanence ( Capacity of being aware of something in its absence )
  • self-awareness
  • Sense of time.
  • Imagination, visualization of the future.
  • Reading the mind of others ( Undereestanding others and imagining yourself as them, or empathizing with others )
  • Language and complex communication.

Components of Intelligenece:

In a nutshell Intelligence is the ability to solve problems.

  • senses
  • memory
  • Learning
  • Library of knowledge:
    • Associations
    • Connections
    • echanical / physics
  • Creativity
  • Using tools
  • Planning
  • Culture
  • Colaboration