Quantum physics Definition and 728 Threads

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    Question about an electric circuit and quantum physics

    So, I've had an argument with a friend of mine about how electrons behave in an electric circuit. He doesn't even know what quantum physics is and I have yet to explain it to him, but the question I'm asking my self is this: Let's say we have an electrical circuit similar to this one...
  2. A

    What is the significance of the number 137 in quantum physics?

    What is the significance of the number 137 in quantum physics?? What is the significance of the number 137 in quantum physics??
  3. K

    Quantum Physics I Tough Normalization Integral Help

    I am pretty sure that I'm doing this right but the integral for normalization seems impossible. Here is the question: Normalize this wave function. psi(x,t)=Axe^(-sqrt(km)/2h)*x^2))*e^(-i(3/2)(sqrt(k/m)*t) for -infinity<x<+infinity where k and A are constants and m is given. I used...
  4. S

    Quantum physics and technology

    Hi, i have learned some basic principles of quantum physics and and know that quantum physics has led to improvements in computers and technology. But can someone please explain to me the details on how quantum theory has improved chip size or gave way to ipods, I am i even right? did quantum...
  5. H

    What Is the Difference Between Color Neutral and Colorless in Quantum Physics?

    Basics on Quantum Physics... I have Two basic Questions which I need an easy, simple answer... First is...What is Spin of a particle? any simple way to define it?
  6. R

    How Is the Angle of Electron Reflection Determined in Quantum Experiments?

    Homework Statement For this question, h= 6.63×10–34 J.s, c = 3×108 m/s, me= 9.11×10–31 kg, e=1.6×10–19 C. Electrons are accelerated from rest by a voltage of 78.0 V. After that acceleration their speed is 5230000 m/s, their linear momentum is 4.77×10-24 and their De Broglie wavelength is...
  7. S

    Quantum Physics: Fourier transform of a function

    Homework Statement Let \phi (k) be the Fourier transform of the function \psi (x). Determine the Fourier transform of e^{iax} \psi (x) and discuss the physical interpretation of this result.Homework Equations (1) \tilde{f} (k) = \frac{1}{\sqrt{2 \pi}} \int{f (x) e^{-ikx} dx} (2) \psi...
  8. B

    Quantum physics- atomic states

    Homework Statement Give the full designation (e.g. 3P0) for all possible singlet, doublet, triplet and quartet S, P and D atomic states. The Attempt at a Solution I don't understand this question at all! Up to which values does the angular momentum (supscript) and multiplicity...
  9. 2

    Unsure about a part of quantum physics

    hi i resently read about Schrödinger's experiment called the Schrödinger's cat experiment which states that things don't exist if not mesured and then exist when they are mesured so then that should mean we can minipulate space and time. As i get it, it would be like somone says there are three...
  10. W

    Basic Quantum Physics - Particle(s) in a (3D) Box

    Homework Statement A system of 20 neutrons are confined in the region 0<x<3L 0<y<L 0<z<2L With L=10^{-15}m If each eigenstate can accept 2 neutrons (corresponding to the 2 possible spin states) what is the total kinetic energy of the system? Homework Equations I found the...
  11. L

    Is this why relativity and quantum physics don't mix?

    In one of Feynmans messenger lectures he proved that relativity implies local conservation of energy using the lagrangian (energy can't jump from one place to another). In the atom of quantum theory the electron jumps around in various discrete orbits. This seems like a contradiction. Is this...
  12. I

    Autism thinking and quantum physics

    Hi, this is my first thread, and my question is; to witch degree can an autist thinker(comprehending via association through different fields such as music) learn quantum phyisics without math?
  13. C

    Why sub-classical physics and quantum physics

    Why sub-classical physics and quantum physics, can not be unity between the two up?
  14. E

    What is the Nuclear Angular Momentum Quantum Number?

    Homework Statement An energy level of a certain isolated atom is split into three components by the hyperfine interaction coupling of the electronic and nuclear angular momenta. The quantum number j , specifying the magnitude of the total electronic angular momentum for the level, has the...
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    Programs Is it possible to double major in Astro & Quantum Physics?

    I want to double major in AstroPhysics and Quantum Mechanics. But considering the two work on different scales (Sizes of matter- One Celestial, the other, Sub Atomic), is it an unrealistic goal? The two fields are at odds at the moment, so I'm starting to have doubts as to whether or not it's a...
  16. W

    Quantum physics, randomness and its influence on the arrow of time

    Hi, I have a question which I've been pondering over and would like to have an anwser to. I'm not schooled in physics so I may be using bad terminology which you're welcome to point out of course. Anyway my question mainly has to do with the randomness in quantum physics. I know that the...
  17. R

    Quantum Physics Books: Recommendations India (Wiley, Pearson)

    hello everyone.i need you ppl to recommend a quantum physics or modern physics book for reference.i stay in india. Wiley publication and Pearson Education are two publisher which i knw.u can suggest any other but good ones.
  18. R

    Where Can I Find a Summer Quantum Mechanics Course?

    Hello, I was hoping someone can help with some information. I was in my last year, and I needed to pass quantum mechanics to graduate. Unfortunately, I got a failing grade and will have to wait till next spring to retake it. I was wondering if anyone knows a college that offers a quantum...
  19. R

    Can Quantum Physics be weaponized?

    Are there any theoretical applications of quantum physics that could in the future lead to weapons in the same way that special relativity led to nuclear weapons?
  20. P

    Can Quantum Physics Be Made Accessible to Everyone?

    Hello, world. This is my first post here...and an ambitious one it is indeed. I'm 15 years of age (I don't know how that is proportionally to the main contributors here, but anyway) and it has occurred to me that there exists a mysterious ether in the non-quantum literate world that it is an...
  21. K

    Quantum physics, particle in a circle

    Quantum physics, I believe Lz is the term for angular momentum. I have a one dimensional system with a particle with mass M and it's moving a long a circle with radius R. a)Use Lz=MvR to express the particle kinetic energi with help of Lz. Then use the substituion that L_z\rightarrow...
  22. S

    How Do You Determine the Allowed Radii in a Quantized Angular Momentum Scenario?

    Homework Statement A particle of charge q and a mass m, moving with a constant speed v, perpendicular to a constant magnetic field B, follows a circular path. If in this case the angular momentum about the center of this circle is quantized so that mvr_n = 2nh, determine the allowed radii for...
  23. M

    Can someone explain this quantum physics concepts to me?

    I don't understand how matter can be transformed to light and light can be transformed into matter? Also, how exactly does this happen when something happens to one particle and something equivalent happens to another particle of the same type on the other end of the Earth instantaneously...
  24. M

    Is 'The Secret Law of Attraction' considered quantum physics? Do you support it?

    I have seen the movie 'The Secret Law of Attraction'. It seems to remind my of quantum physics a bit. However, I read about the concept behind the creation of the movie and have come across a lot of controversy. Some people are saying the law of attraction usually does not take the function of...
  25. S

    HELP ME, trapped in Aristotelian conception but must learn quantum physics

    So I went to St. Andrews University with the unbelievably stupid idea that I would be able to "handle" their physics. My university, reading only the course description, thought that fourth semester physics was equivalent to Baylor's second semester physics. I soon realized that they only...
  26. A

    Schools Can You Get a Physics Doctorate Without an MSc in Quantum Physics?

    Hello, I was wondering if a person majoring in physics takes quantum physics classes too, and if a person with a BSc in physics get a doctorate without having an MSc in physics. Thanks for the help. :D
  27. L

    Any good CHEAP quantum physics text books?

    I'm just looking for an affordable quantum physics textbook, I am not quite a beginner at this, maybe intermediate if you call it.
  28. G

    The Wonders of Quantum Physics as a Teen: Tips and College Insights

    Hi, I am just a teenager but I am very interested and dedicated to learning quantum physics, i want to be a theoretical physicist or astrophysicist, something like that. But I am trying to learn as much as I can using books, tv, and the internet mostly. Sometimes i have a hard time...
  29. S

    Does the energy of a photon determine its size in relation to an electron?

    According to Einstien's theory, energy of one photon is absorbed by one electron. Is this photon is smaller than electron? If not, why energy of photon is not absorbed by other subatomic particles.
  30. T

    Classical Physcics VS Quantum Physics

    Hello people, its been a while since i used physics forums. My assignment is basically a comparison between classical physics and the Quantum physics and to explain why we don't use classical physics. While surfing on the web, i came across a text implying that the definitions of light, energy...
  31. C

    Exploring Quantum Physics: A Comprehensive Guide

    i am writing a paper on quantum physics. anyone have any good websites that could help me find out everything i need to know?
  32. S

    Particle physics and quantum physics

    particle physics and quantum physics... can u tell me some difference between particle physics and quantum physics
  33. F

    Quantum Physics and Black holes

    What does quantum physics have to say about black holes?
  34. P

    Quantum Physics - Measurement/Eigenvalues(functions)

    Homework Statement For a certain system, an observable A has eigenvalues 1 and -1, with corresponding eigenfunctions u_+ and u_-. Another observable B also has eigenvalues 1 and -1, but with corresponding eigenfunctions: v_+ = \frac{u_+ + u_1}{\sqrt{2}} v_- = \frac{u_+ -...
  35. K

    Time noninvariance in quantum physics

    The discussion about the existence and importance of experimental study of the strong time noninvariance in quantum physics lasts more than 10 years (see arXiv:hep-ph/0002084, physics/0612089v2 and others). Its essence is that the inequality of forward and reversed processes is quite usual in...
  36. S

    Probabilistics of Quantum Physics

    Hey Guys and Gals! This is my first post ever! I would like to discuss something i have recently thought about. If classical physics is deterministic and allows us to create laws, since quantum physics is probabilistic can we ever create any quantum physics laws? (i don't think there...
  37. N

    How Does Antenna Spacing Affect Signal Intensity at a Distance?

    Homework Statement The four antennas are arranged in a square with side length d and each of the antennas has an adjustable phase of the radiation emitted. The intensity of radiation emitted by each antenna is I1 with wavelength λ. A receiver is placed at locations A (at the center of the...
  38. N

    Superposition and Coherence in quantum physics

    I want a clarification in the idea of superposition principle.Perhaps,I should rather say that the distinction of superposition principle in QM and in classical physics. Few weeks back,I was spending time with Gottfried's book. He explains the novelty of superposition principle with the help...
  39. A

    Using Perturbation Theory to Calculate Probability in Quantum Mechanics

    Quantum Physics Help! Homework Statement The spring constant for a particle in the ground state of a simple harmonic oscillator changes by a factor a^4 instantaneously, what is the probability that the particle is observed in the ground state of the new potential immediately following the...
  40. M

    Gravitational waves and quantum physics

    If gravitational waves have such tiny amplitudes (typically several orders of magnitude smaller than a proton), then why do we model them entirely in terms of general relativity? Aren't quantum effects important at this scale?
  41. E

    Quantum physics and equivalence principle

    I read some articles, where equivalence principle is no more valid in quantum area. One example are neutrinos, changing colours (electron, muon, tauon neutrino). But formulae are not derived from fundaments, so I do not understand, where it is the catch. I read also about COW experiment...
  42. A

    Does Observation Influence Reality in Quantum Physics?

    I'm not sure if this is the right forum for my question so here it goes. If not, let me know and I'll be happy to move on. I've been reading information written by Fred A. Wolf and J. Sarfatti and I think that I'm getting carried away with how I'm interpreting their information. According to...
  43. A

    Exploring the Link Between Quantum Physics & Consciousness: Why Not?

    Why is it that more physicists aren't looking at possible connections between quantum physics and consciousness like Wolf and Sarfatti ? Seriously... is there no money in it? Not testable? Is it considered career suicide? What is it? Just curious...
  44. S

    Implications of Quantum physics

    I just want to make sure I understand some of the greater implications of discoveries made by quantum physics experiments and theories like the double slit experiment and Schroedinger's cat. Because observation effects results, it becomes clear that an observer cannot extract themselves from...
  45. R

    Definitoon of trajectory in quantum physics, especially in path integrals

    What is the correct way to use the term trajectory in physics when discussin path integral forumaltion calculations. Here is the sentence i am trying to complete and am unsure if i may use the term trajectory: So the wavefunction offers a much more simplistic and perhaps more beautiful way to...
  46. D

    Quantum physics - time dependant changes

    Homework Statement a particle of mass m is in the groundstate of a 1D box with width a. the box then expands rapidly and symmetrically to width 2a. i). What is the probability that the particle is in the new groundstate immediately after the expansion? and ii). how rapid must this expansion be...
  47. 6

    Is the Hall Effect Part of Quantum Physics?

    Is the Hall Effect quantum physics?
  48. F

    What Are the Best Books on the Evolution of Quantum Mechanics?

    Does anyone know of any books on the history of quantum mechanics? I'd ideally like an in depth coverage of the experimental results and theoretical developments, with references to original papers. A complete treatment of non-relativistic quantum mechanics (from pre-Planck to Dirac) would be...
  49. M

    The quantum physics of time travel

    anyone read or have opinions on The Quantum Physics of Time Travel by David Deutsch and Michael Lockwood? He talks about closed time like curves and if we followed them it would end up taking us to the past to participate in events, shake hands with former selves etc I was a little...
  50. H

    Quantum Physics Debate, Is It Relevant?

    I have recently been doing research and have found that The Theory of Relativity is not accurate enough to predict paths of the planet's orbit. I would also like to call to attention that gravity and quantum physics are flawed in one way or another. So in turn I would like to have some ideas...
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