José A. Estarelles dice: 19 abril, 2022 a las 11:42 am Buenas, Soy el traductor de esta obra de Wolfgang Smith. Tengo que decir que no es cierto que el autor desconozca o ignore la decoherencia, ni lo que algunos quieren extraer de ello, como demuestra su respuesta de 2019 al doctor McAndrew, «To Be or Not To Be an Apple» (philos-sophia.org/be-or-not-be-apple): “El famoso ‘problema de la medición’, … a pesar de las famosas pretensiones en sentido contrario, en realidad no se ha resuelto hasta ahora: ni el tour de force de la mecánica de Bohm, ni la teoría de los ‘muchos mundos’, ni la ‘decoherencia’, ni ninguna otra de sus propuestas [de la comunidad de física] ha logrado aún resolver ese dilema.” En fin, el colapso del vector de estado para nada es un “problema obsoleto”, ni “de interés histórico”. Es una cuestión plenamente vigente, por incómoda que sea para tantos. Entra Smith más en la decoherencia en los capítulos 2 y 4 de su título “The Vertical Ascent” (2020), que en gran medida se pueden consultar en la web del autor: “The Tripartite Wholeness” (philos-sophia.org/the-tripartite-wholeness) y “Lost in Math: The Particle Physics Quandary” (philos-sophia.org/particle-physics-quandary) donde, como en otro acertado comentario aquí, también se menciona a Sabine Hossenfelder. Dicho esto, y dejando a un lado el desafío que plantea la misma decoherencia para la interpretación totalista de la física cuántica, supongo que verá por qué me parece que esta reseña que hace al libro está exenta de valor crítico, aunque agradezco el interés prestado. Responder Francisco R. Villatoro dice: 19 abril, 2022 a las 1:5

Alf dice: 21 abril, 2022 a las 7:48 pm Como curiosidad en la historia de la física ¿ Desde cuando y porque ( me refiero a pruebas empíricas o formalismos matemáticos ) han dejado obsoleto a los procesos R (como colapso del vector de estado ) Responder Francisco R. Villatoro dice: 22 abril, 2022 a las 12:59 am Alf, la idea de los pioneros era que el colapso de la función de onda era un mecanismo dinámico diferente de la evolución unitaria. El formalismo de integrales de camino en mecánica cuántica y la interpretación de muchos mundos fueron cambiando la mentalidad de la mayoría de los físicos poco a poco. Durante la década de los 1970 la idea de que la única dinámica necesaria es la evolución unitaria y de que el colapso es un artificio innecesario se fue imponiendo poco a poco. A finales de la década de los 1970, los libros de texto de mecánica cuántica empezaron a omitir el problema de la medida como un problema que todo físico tuviera que conocer y el colapso dejó de mencionarse en la mayoría de dichos libros de texto, que ya solo discutían la evolución unitaria. Ya en los 1980 el colapso quedó degradado a las monografías específicas y a artículos de investigación sobre física más allá de la mecánica cuántica. A pesar de ello, la idea de que el colapso es un concepto obsoleto (además de innecesario) no se ha impuesto hasta principios del siglo XXI. Responder Alf dice: 22 abril, 2022

joan dice: 18 abril, 2022 a las 3:17 pm que opinais de este libro: EL ENIGMA CUANTICO: ENCUENTROS ENTRE LA FISICA Y LA CONCIENCIA BRUCE ROSENBLUM FRED KUTTNER Responder Francisco R. Villatoro dice: 19 abril, 2022 a las 9:32 am Joan, el libro de Rosenblum y Kuttner parece empezar bien con su discusión de la historia que antecede a EPR y las desigualdades de Bell, pero entonces, cuando llega al nudo de la cuestión del «enigma cuántico» se hunde en la miseria; en lugar de discutir lo que se sabe sobre el asunto derrapa con el tema de la conciencia y acaba engañando al lector que esperaba una discusión sobre el «enigma cuántico» y se encuentra una discusión metafísica que no está relacionada ni con el título, ni con el resto del libro. En mi opinión, un libro bien escrito, de lectura fácil, pero muy poco recomendable para quien quiera aprender algo sobre física cuántica.

Francisco R. Villatoro dice: 15 abril, 2022 a las 9:48 am Javi, el colapso de la función de onda no existe, es un concepto obsoleto. La evolución unitaria se aplica tanto al sistema de medida como al sistema medido durante todo el proceso de la medida; cuando el sistema de medida es tan complicado que no se puede describir en pie de igualdad al sistema medido, se recurre a actualizar el estado del sistema medido tras la conclusión de la medida para hacer compatibles la evolución de ambos (esto es lo que se llama proyección del estado tras la medida). Si esta actualización se realiza de forma correcta, en futuras medidas el resultado será compatible con dicha actualización; si se realiza de forma incorrecta, habrá discrepancias, que señalarán que se ha realizado mal. No hay ningún misterio en todo esto.

Smith es físico, matemático y filósofo

Wolfgang Smith, «El enigma cuántico. Descubriendo la clave oculta», Sekotia (2021) [188 pp.], traducido por José Antonio Estarelles

Fernando dice: 16 abril, 2022 a las 5:40 am Hola, Francis, Primero de todo, felicitarte por tu sin duda extraordinaria labor en este blog, que es digna de elogio. En segundo lugar, y ya en relación al tema aquí abordado, me ha sorprendido tu afirmación categórica acerca de la inexistencia del colapso, pues si bien es cierto que ésta es una postura sostenida por muchos físicos que trabajan en el programa de Decoherencia Cuántica, no menos cierto es que no es compartida por toda la comunidad científica. De hecho, siendo rigurosos, se trata de una corriente del pensamiento no avalada aún de manera general por los resultados matemáticos y experimentales derivados de dicho programa de investigación. Sin ir más lejos, dentro de dicho marco matemático, el colapso del sistema-aparato es aparente, pues aunque como consecuencia del entorno el operador densidad reducido del sistema-aparato acabe teniendo finalmente la forma característica de un estado mixto, el operador densidad del sistema global sistema-aparato-entorno sigue siendo el de un estado puro, por lo que el sistema global sigue estando en un estado superposición, y por ende, el observable medido sigue sin estar bien definido según el formalismo cuántico. Es más, al tomar la traza parcial sobre los estados del entorno para hacer cálculos sobre el operador densidad reducido del sistema-aparato, no estamos teniendo en cuenta la coherencia de fase global entre el sistema, el aparato y el entorno, por lo que el mecanismo de decoherencia en ningún momento afecta a dicha fase. En consecuencia, el sistema-aparato-entorno sigue en un estado superposición, no legitimándonos nada a afirmar lo contrario. Es por ello que no se puede afirmar que se haya producido un colapso real de algo, ni tampoco que la Decoherencia resuelva el problema de la lectura definida del aparato de medición. Me consta, no obstante, que el concepto de envarianza introducido por Zurek resulta lo suficientemente prometedor como para poder resolver quizás los problemas a los que conduce el citado operador densidad reducido, pero desconozco si lo ha llegado lograr. Si lo ha hecho, te agradecería me pasaras algún «paper» sobre ello para poder estar completamente actualizado. Incluso si dispusieras de tiempo y te apeteciera, estaría bien poder discutirlo privadamente de físico a físico.

Enrique dice: 17 abril, 2022 a las 5:40 pm Hola Juan, aún coincidiendo plenamente con casi todo tu planteamiento, la teoría cuántica de campos no resuelve el conocido como problema de la medida, que se ilustra, de una forma muy sencilla, con el experimento de la doble rendija: cuando no se mide por donde pasa, el electrón se comporta como onda, cuando se mide se comporta como corpúsculo. Es precisamente la decoherencia la que señala que el aparato de medida, al ser un objeto externo al sistema que hemos considerado y que además está formado por una enorme cantidad de partículas, rompe la coherencia del sistema, impidiendo que se produzca la interferencia y, por tanto, que veamos el electrón como onda.

Enrique dice: 16 abril, 2022 a las 11:40 am Soy físico. Llevo más de 20 años intentando convencer a colegas y amigos de que la decoherencia es la interpretación correcta al problema de la medida en cuántica. La mayor objeción que he encontrado en los demás para aceptar esta idea no es su coherencia o lógica, sino que, ni en los libros de texto, ni en los de divulgación y en la mayoría de los artículos científicos, de lo que se habla es de colapso de la función de onda o en el mejor de los casos de pérdida de información de la matriz densidad (interpretación de Von Newman). He llegado a la conclusión de que, en los libros de divulgación se habla de colapso de la función de onda porque permite decir cosas «extrañas» sobre la física y eso vende. Por otra parte, los grandes libros de texto sobre cuántica se escribieron hace 40 años o más y fueron escritos por autores que habían estudiado las bases de la cuántica 40 años antes y por tanto, cuando el colapso de la función de onda era incuestionable. En mi opinión faltan de 10 a 20 años para veamos libros de divulgación que incluyan la decoherencia como solución al problema de la medida. Yo solo vi, en 1995, una pincelada sobre lo que era la decoherencia (apenas unas líneas) en el libro «El quark y el jaguar» del gran Murray Gell-Mann. Después de aquello, nada.

He continues by comparing open works to Quantum mechanics, and he arrives at the conclusion that open works are more like Einstein's idea of the universe, which is governed by precise laws but seems random at first. The artist in those open works arranges the work carefully so it could be re-organized by another but still keep the original voice or intent of the artist.

First, what do I mean by meta-stable? It’s in reference to an article by Scott H Young - 7 Rules for Staying Productive Long-Term. In it, Scott describes a concept in physics where something is stable but small perturbations can cause it to break, and not able to go back to its starting position after a small push. The example he gives is a pendulum, perfectly balanced at the top; when pushed will not return to its starting point. Contrast this with a pendulum’s other stable point, the bottom. When pushed, it’ll return to that starting point easily.

Ryan Usher says: January 22, 2022 at 6:19 pm “…I don’t at all understand why Quanta chose to cover this.” This is something I find myself wondering as well, and it’s not the first time Quanta has fallen prey to this kind of hype–and I characterize it in that way to be generous to Quanta in the face of my cynicism. So I decided to waste a couple of hours to come up with the following:

gravitational míreming woh* This text was recognized by the built-in Ocrad engine. A better transcription may be attained by right clicking on the selection and changing the OCR engine to "Tesseract" (under the "Language" menu). This message can be removed in the future by unchecking "OCR Disclaimer" (under the Options menu). More info: http://projectnaptha.com/ocrad

Cual es el sitio Web que promocionan?

gravity on the poles in a bit larger

Physics Hamiltonian for the zeros of the Riemann Zeta function (2016) General Relativity and Cosmology: Unsolved Questions and Future Directions (2016) There are no particles, there are only fields (2012) Would Bohr be born if Bohm were born before Born? (2007) The holographic solution - why general relativity must be understood in terms of strings (2004) Measurement of subpicosecond time intervals between two photons by Interference (1987) Bertlmann’s socks and the nature of reality (1981) More is different (1972) On the Einstein Podolsky Rosen Paradox (1964) Deterministic Nonperiodic Flow (1962) There's Plenty of Room at the Bottom (1959) Forms of Relativistic Dynamics (1949) What is life? (1944) Can Quantum-Mechanical Description of Physical Reality Be Considered Complete? (1935) Possible Existence of a Neutron (1932) On the electrodynamics of moving bodies (1905)

Treatise was not to expound his theory finally to the world, but to educate himself by presenting a view of the stage he had reached.

Maxwell's advice was to read the four parts of the Treatise in parallel rather than in sequence.

Below are some reflection questions.

The spiritual vision of the Bauhaus was a faith in people’s ability to transform society for good by breaking down divisions and working together toward a common purpose.

General relativity implies that information gets destroyed; quantum theory says it’s preserved. Hence the paradox.

In thermodynamics, a diathermal wall between two thermodynamic systems allows heat transfer but do not allow transfer of matter across it

We may assume that Anaximander somehow had to defend his bold theory of the free-floating, unsupported earth against the obvious question of why the earth does not fall. Aristotle’s version of Anaximander’s argument runs like this: “But there are some who say that it (namely, the earth) stays where it is because of equality, such as among the ancients Anaximander. For that which is situated in the center and at equal distances from the extremes, has no inclination whatsoever to move up rather than down or sideways; and since it is impossible to move in opposite directions at the same time, it necessarily stays where it is.” (De caelo 295b10ff., DK 12A26) Many authors have pointed to the fact that this is the first known example of an argument that is based on the principle of sufficient reason (the principle that for everything which occurs there is a reason or explanation for why it occurs, and why this way rather than that).

These observations were made with the naked eye and with the help of some simple instruments as the gnomon. The Babylonians, in particular, were rather advanced observers. Archeologists have found an abundance of cuneiform texts on astronomical observations. In contrast, there exists only one report of an observation made by Anaximander, which concerns the date on which the Pleiades set in the morning. This is no coincidence, for Anaximander’s merits do not lie in the field of observational astronomy, unlike the Babylonians and the Egyptians, but in that of speculative astronomy. We may discern three of his astronomical speculations: (1) that the celestial bodies make full circles and pass also beneath the earth, (2) that the earth floats free and unsupported in space, and (3) that the celestial bodies lie behind one another. Notwithstanding their rather primitive outlook, these three propositions, which make up the core of Anaximander’s astronomy, meant a tremendous jump forward and constitute the origin of our Western concept of the universe.

The Internet, an immeasurably powerful computing system, is subsuming most of our other intellectual technologies. It’s becoming our map and our clock, our printing press and our typewriter, our calculator and our telephone, and our radio and TV.

The largest collection of Isaac Newton's papers has gone digital, committing to open-access posterity the works of one of history's greatest scientist. Among the works shared online by the Cambridge Digital Library are Newton's own annotated copy of Principia Mathematica and the 'Waste Book,' the notebook in which a young Newton worked out the principles of calculus.

It compels us to understand that not every acceleration results from a universal force and this is the essential idea of the first law.

Say, for instance, a hypothetical self-driving car is sold as being the safest on the market. One of the factors that makes it safer is that it “knows” when a big truck pulls up along its left side and automatically moves itself three inches to the right while still remaining in its own lane. But what if a cyclist or motorcycle happens to be pulling up on the right at the same time and is thus killed because of this safety feature?

Magnetic materials are always made of metal, but not all metals are magnetic

Nevertheless, physicists continue to select theories based on the same three criteria of beauty: simplicity, naturalness, and elegance.

I think it’s time we take a lesson from the history of science. Beauty does not have a good track record as a guide for theory-development.

History has a second lesson. Even though beauty was arguably a strong personal motivator for many physicists, the problems that led to breakthroughs were not merely aesthetic misgivings – they were mathematical contradictions. Einstein, for example, abolished absolute time because it was in contradiction with Maxwell’s electromagnetism, thereby creating special relativity. He then resolved the conflict between special relativity and Newtonian gravity, which gave him general relativity. Dirac later removed the disagreement between special relativity and quantum mechanics, which led to the development of the quantum field theories which we still use in particle physics today.

My conclusion from this long line of null results is that when physics tries to rectify a perceived lack of beauty, we waste time on problems that aren’t really problems. Physicists must rethink their methods, now – before we start discussing whether the world needs a next larger particle collider or yet another dark matter search.

In some sense, by studying one model deeply enough, we can study them all.

Their findings indicate that the set of all quantum field theories forms a unique mathematical structure, one that does indeed pull itself up by its own bootstraps, which means it can be understood on its own terms.

The notion that counting more shapes in the sky will reveal more details of the Big Bang is implied in a central principle of quantum physics known as “unitarity.” Unitarity dictates that the probabilities of all possible quantum states of the universe must add up to one, now and forever; thus, information, which is stored in quantum states, can never be lost — only scrambled. This means that all information about the birth of the cosmos remains encoded in its present state, and the more precisely cosmologists know the latter, the more they can learn about the former.

This is, I thought, little more than an analogy with Boyle’s Law, one of the most striking early successes of the scientific revolution, which holds that the pressure and volume of a fixed amount of gas are inversely proportional.  Release the contents from a steel cylinder into a balloon and the container expands.  But it still contains no more gas than before.  Something like that must have been in the mind of the first person who first spoke of “inflating” the currency. From there it was a short jump to the way that classical quantity theory relies on the principle of plenitude – the age-old assumption, inherited from Plato, that there can be nothing truly new under the sun, that the collection of goods of “general price level” were somehow fixed.

Come on, harvest me! I’ll just change your world some more.

I think there is some interesting physics here. In particular, there is something curious about the difference between static and kinetic friction. First, let me make some observations and assumptions.

448-page preprint paper

Wynn Education Centre Pte Ltd

Wynn Education Centre Pte Ltd

Wynn Education Centre Pte Ltd

Wynn Education Centre Pte Ltd

tunnel splitting

Solve problems involving mixtures of gases

Define a thermodynamic process

Sempre ricordando che quando si parla di sfericità, l’elettrone non deve essere pensato come una pallina: si tratta di una particella elementare, dunque non strutturata e indivisibile, e per forma si intende in realtà la simmetria delle sue interazioni con i campi esterni, con altre cariche.

Since water is denser than air, and the reflection is diffuse. A lot of light is internally reflected, thereof, increasing the probability of absorption at surface.

This is because the light now has a layer of water to go through. And due to the reflectance of water, not all light at the air-liquid-interface (border between air and water) goes through the water. Some of it is reflected.

There are two types of reflection (two ways the wave can be thrown back). Specular Diffuse

is 100%,

to face the very

lead ion nuclei

B-hadron

removing

selected

Expand the trigger description for the paper draft.

that combines the outputs of IP3D and SV1,

Quantum Realism: A virtual reality would be subject to virtual time, where each processing cycle is one "tick." Every gamer knows that when the computer is busy the screen lags—game time slows down under load. Likewise, time in our world slows down with speed or near massive bodies, suggesting that it is virtual. So the rocket twin only aged a year because that was all the processing cycles the system busy moving him could spare. What changed was his virtual time.

unitary operator is a surjective bounded operator

Deep learning approach based on dimensionality reduction for designing electromagnetic nanostructures

Physics-guided Neural Networks (PGNNs)

Opening the black box of deep learning

Using Machine Learning to Predict the Evolution of Physics Research

DeepSphere: Efficient spherical Convolutional Neural Network with HEALPix sampling for cosmological applications

Toward an AI Physicist for Unsupervised Learning

The establishing of this mutual relationship between technology and physics is correct. But it remains a merely historiological establishing of facts and says nothing about that in which this mutual relationship is grounded. The decisive question still remains: Of what essence is modern technology that it thinks of putting exact science to use?

we found advanced math and science courses advertised but not actually offered and specialized STEM programs eroded or discontinued within a few years of inception.

Yet, across the country, 2 in 5 high schools don't offer physics, according to an Education Week Research Center analysis of data from the U.S. Department of Education's office for civil rights.

similarities between the two

In 2013, François Englert and Peter Higgs were awarded the Nobel Prize in Physics for the development of the Higgs mechanism.

It is encoded in a compact description, the so-called 'Lagrangian', which even fits on t-shirts and coffee mugs.

Actually, the addition of \text{h}.\text{c}. is not required for term 2, since term 2 is self-adjoint.

we recommend using the term 'transformation' instead of 'decay', as this more accurately describes the physical process

where μ and ν are Lorentz indices representing the spacetime components

Feynman diagrams

quantum field theory

The latest success was the verification of the Brout–Englert–Higgs field by ATLAS and CMS at CERN's Large Hadron Collider in 2012. Both experiments successfully detected the quantised excitation of the BEH field—the so-called Higgs boson.

the Brout–Englert–Higgs field interacts with particles that have mass (all particles except the gluon and the photon)

Matter particles can be divided into three groups: quarks (q) and antiquarks (\bar{q}); electrically charged leptons (\ell) and antileptons (\bar{\ell}); neutrinos (ν) and antineutrinos (\bar{\nu}). Gluons (g) couple to colour charge, which only quarks, antiquarks, and gluons themselves, have.

Goel’s specialty is “nanobiophysics” — she studies how physics and nanotechnology can effect biology and medicine.

The following is a statement of the laws of physics, not just my own personal opinion. "When power is Variable, Power controls airspeed." "When power is fixed, Pitch controls airspeed." In general, airplanes go where you point them, and go as fast as the power dictates. This is the easiest way to fly, and it works in all airplanes.

π2/90

“What’s the world resting on now, without the tortoise to hold it up?”