Quantum Physics Forum

Join in expert discussion on quantum physics. Quantum physics is the mathematical description of the motion and interaction of subatomic particles. Quantum Mechanics and Field Theory.

Threads

Graduate What proof is there that quantum states collapse on measurement?

  • hdsncts
  • · Replies 3 ·
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Graduate Is the Group Velocity Double the Phase Velocity at Low Velocities?

  • RANDHIR SINGH
  • · Replies 1 ·
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Graduate Hermitian adjoint of the time derivative?

  • leright
  • · Replies 7 ·
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7

Graduate Quantum Entanglement and retrocausality

  • onigiri
  • · Replies 8 ·
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8

Graduate Spin Exchange in Fermi Sea - Evaluating S_x \cdot S_{x+1}

  • andrewm
  • · Replies 1 ·
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Graduate A relativistic quantum theory of gravity

  • meopemuk
  • · Replies 49 ·
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Graduate Why does the sum ∑_x e^{i(k-k')x} equal the Kronecker delta?

  • andrewm
  • · Replies 4 ·
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4

Graduate Vacuum state of the Klein-Gordon field

  • knobelc
  • · Replies 9 ·
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9

High School My First Double Slit Experiment

  • thenewmans
  • · Replies 4 ·
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4

Graduate Derivative inside, outside time ordering

  • ismaili
  • · Replies 4 ·
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4

Graduate Stern-Gerlach apparatus with excited helium: why aren't Mj states equally probable?

  • folgorant
  • · Replies 7 ·
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Graduate Quantum Physics, Causality, and Logic

  • avant-garde
  • · Replies 2 ·
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Graduate Light Interaction with Electrons in Glass

  • thenewmans
  • · Replies 7 ·
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7

Graduate Why Davisson and Germer proved electron waves over particle scattering

  • student85
  • · Replies 3 ·
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3

Graduate Calculating Broglie Wavelength for Helium Superfluid

  • glueball8
  • · Replies 3 ·
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3

Undergrad Can We See Photons With Naked Eye?

  • Sabradin
  • · Replies 21 ·
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Graduate Revolutionary Experiment Confirms Incompleteness of Quantum Mechanics

  • Rade
  • · Replies 35 ·
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Graduate Photons Detector not yielding which-path info.

  • wampeter
  • · Replies 44 ·
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Graduate Commuting Operators in Sequential Stern Gerlach Experiment

  • maverick280857
  • · Replies 16 ·
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16

Graduate Measurement and Stern Gerlach Experiments review articles?

  • maverick280857
  • · Replies 3 ·
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3

Undergrad Distance Between Atoms: How to Measure

  • Legion81
  • · Replies 8 ·
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8

Graduate Linus Pauling's Hydrogen Atom: MVR=nh/2pi?

  • The_ArtofScience
  • · Replies 1 ·
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1

Graduate Quantum Mechanics: Learning Bra-Ket Notation

  • Reedeegi
  • · Replies 4 ·
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4

Graduate Coherent States of the Harmonic Oscillator

  • tshafer
  • · Replies 2 ·
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Graduate Questions about the Density Operator Formulation of Quantum Mechanics

  • CPL.Luke
  • · Replies 3 ·
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3

Graduate Does turning off a measuring device still collapse the wave function?

  • Sabradin
  • · Replies 11 ·
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11

Graduate How Do Quantum Computers Use Qubits in Superposition for Calculations?

  • Nick89
  • · Replies 2 ·
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Graduate Why doesn't photon helicity equal the spin magnitude?

  • Usaf Moji
  • · Replies 2 ·
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2

Graduate Does the universe need a wave function to describe it?

  • C Rob
  • · Replies 3 ·
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3

Graduate How do I calculate the initial alpha for an iterative process in a finite well?

  • bluestar
  • · Replies 3 ·
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3

Graduate Massless free field equation -> Maxwell's eqn.

  • lark
  • · Replies 10 ·
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10

Graduate What is a wave function and how does it describe the wave nature of a particle?

  • janakiraman
  • · Replies 4 ·
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4

Graduate Concept of a renormalizable theory in Weinberg's feild theory book

  • nughret
  • · Replies 5 ·
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5

Undergrad What does the Hamiltonian of a system describe?

  • janakiraman
  • · Replies 13 ·
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Graduate Quantum computing and Nanoscale CAD

  • BWV
  • · Replies 5 ·
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Graduate What Would Happen If 2 Protons Collided?

  • Dumbo
  • · Replies 1 ·
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Graduate Solving Fermions: Finding States & Energies

  • guidob
  • · Replies 4 ·
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4

Undergrad Why is the Weak Force So Weak?

  • carus88
  • · Replies 2 ·
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Graduate Why spinor bec is called ''spinor bec''?

  • wdlang
  • · Replies 1 ·
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Graduate Why Don't Electrons Fall into the Nucleus Despite the Uncertainty Principle?

  • kahoomann
  • · Replies 10 ·
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Graduate What is the difference between chirality and helicity?

  • gremezd
  • · Replies 6 ·
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6

Graduate Projection postulate - can it be verified?

  • ala
  • · Replies 17 ·
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Graduate Dirac delta spherical potential

  • neworder1
  • · Replies 5 ·
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Graduate What Is the Simplest Picture for Entangled Particles?

  • wawenspop
  • · Replies 10 ·
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Graduate Improving the Gottesman-Chuang quantum digital signature scheme

  • Dragonfall
  • · Replies 2 ·
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Graduate Are ghosts Feynman diagram overcounting or longitudinal photons?

  • captain
  • · Replies 1 ·
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Undergrad Finding n for Line Spectra with 400 nm Wavelength

  • pisay
  • · Replies 1 ·
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Undergrad Gravity and its effect on particles/molecules and bonds.

  • g__ritchie
  • · Replies 7 ·
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Undergrad Detecting Single Photon Energy

  • splinewave
  • · Replies 3 ·
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Graduate Questions about some material from Dirac

  • JasonJo
  • · Replies 1 ·
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Graduate Differentiation of an exponential with operators (Peskin p.84)

  • gremezd
  • · Replies 4 ·
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Graduate Is the Integral of the Square of Phase Density Constant in Classical Mechanics?

  • xylai
  • · Replies 1 ·
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Graduate Electrons travel faster than the speed of light

  • epkid08
  • · Replies 90 ·
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Graduate The Principle of Least Action in Quantum Physics

  • lugita15
  • · Replies 10 ·
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Graduate Quantum attraction by exchange of particles

  • yoyoq
  • · Replies 1 ·
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Graduate Why add momentum and energy equations when solving for photon momenta

  • jk4
  • · Replies 3 ·
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Graduate Renormalization in Fluidodynamics

  • random3f
  • · Replies 1 ·
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Graduate Total Spin of Two Particles w/ Spin 1

  • Usaf Moji
  • · Replies 2 ·
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2

High School Basic question on electron, ion and photon excitation

  • guorenguoren
  • · Replies 1 ·
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1

Help with attached file

  • cosmology
  • · Replies 1 ·
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1

Graduate Is there a description of collapse in QFT ?

  • dreynaud
  • · Replies 3 ·
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3

Graduate Pair Production and Momentum Transfer in Photon Interactions

  • jk4
  • · Replies 4 ·
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4

Undergrad Heisenbergs Uncertainty Principle

  • Niles
  • · Replies 38 ·
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Graduate What's wrong with Heisenberg's microscope?

  • kahoomann
  • · Replies 11 ·
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11

Graduate What is the significance of singlets and gauge invariance in particle physics?

  • ledamage
  • · Replies 7 ·
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7

Graduate Is probability a Quantum Observable ?

  • dreynaud
  • · Replies 12 ·
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Graduate Can a cat truly be the observer in Schrödinger's thought experiment?

  • nepofazz
  • · Replies 1 ·
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Undergrad Double slit experiment with barrier between slits and detector

  • netjim66
  • · Replies 3 ·
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3

Graduate What the state of Quantum mechanics (QM) is?

  • xylai
  • · Replies 15 ·
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Graduate Mach-Zehnder Interferometer at Wiki Question

  • daniel29208
  • · Replies 1 ·
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1

Graduate Why is the ground state energy 1/2ℏω, not zero, in the harmonic oscillator?

  • adartsesirhc
  • · Replies 2 ·
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2

Graduate What Is the Role of the Hamiltonian in Quantum Mechanics?

  • Xezlec
  • · Replies 35 ·
2
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35

Graduate Rotate Photon Polarization: 90 Degrees?

  • Dragonfall
  • · Replies 2 ·
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2

Graduate Pauli exclusion principle question

  • drullanorull
  • · Replies 2 ·
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2

Graduate Kinetic Energy in Non-Normalized Particle State

  • jalobo
  • · Replies 1 ·
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1

Graduate Quantizing a two-dimensional Fermion Oscillator

  • jostpuur
  • · Replies 88 ·
3
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Graduate Laser Tube Cavities: Increasing Power w/Mirrors?

  • mharney1268
  • · Replies 4 ·
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4

Graduate Can orthogonal qubits always be distinguished by a measurement?

  • Dragonfall
  • · Replies 3 ·
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3

Graduate Rotating Bose gases, quantum vortices

  • confused_man
  • · Replies 9 ·
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9

Graduate Dimensional Regularization of an Integral

  • Sunset
  • · Replies 2 ·
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2

Graduate What if Planck's Constant was 6.63x10^30?

  • the iron maiden
  • · Replies 15 ·
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15

Graduate Exclusion Principle and Symmetry in Multi-Electron Systems

  • Bobhawke
  • · Replies 13 ·
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13

Graduate R. Slansky, Group theory for unified model building

  • jpg15
  • · Replies 5 ·
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5

Undergrad Why Was "h" Chosen for Planck's Constant?

  • FordPrefect
  • · Replies 3 ·
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3

Graduate How do path amplitudes cancel in Feynman's QED partial reflection?

  • STS816
  • · Replies 5 ·
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5

Graduate Time depending quantum solution

  • timgor
  • · Replies 1 ·
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1

Graduate The dangers of heuristic reasoning

  • Count Iblis
  • · Replies 2 ·
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2

Graduate Clebsch-Gordan coefficients for spin-one particle decomposition

  • Marty
  • · Replies 16 ·
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16

Graduate Particle in 1-D Box: Pressure Force on Wall

  • libai
  • · Replies 1 ·
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1

Graduate What are some common questions about Peskin's QFT book?

  • ismaili
  • · Replies 3 ·
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3

Graduate Is the Born Rule Rooted in Classical Wave Energy Principles?

  • ThomasT
  • · Replies 5 ·
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5

Graduate Destroying interference pattern of classical waves

  • Count Iblis
  • · Replies 6 ·
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6

Graduate Why are Photons Massless? Zach's Questions

  • zwest135
  • · Replies 10 ·
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10

Graduate How does the photon absorption process work in atoms?

  • caybo
  • · Replies 1 ·
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1

Graduate QFT and local gauge invariance

  • losang
  • · Replies 5 ·
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5

Graduate Counter example to the Bloch's theorem?

  • jostpuur
  • · Replies 11 ·
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11

Graduate QFT: Find Poincare Group Generators in QFT

  • udaraabey
  • · Replies 2 ·
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2

Graduate Does the uncertainty principle break symmetry?

  • kahoomann
  • · Replies 5 ·
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5

Graduate Why Does a Wave Packet Better Describe a Particle in Quantum Mechanics?

  • shubhajit
  • · Replies 2 ·
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2

Graduate Understanding Bras and Kets as Vectors and Tensors

  • Phrak
  • · Replies 154 ·
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154