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 LS vs jj couplings and their selection rules

  • bentzy
  • · Replies 3 ·
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3

Undergrad Why is quantum field theory undefined in 3+1 dimensions?

  • HomogenousCow
  • · Replies 11 ·
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11

Undergrad What is attosecond physics?

  • mamdouh
  • · Replies 3 ·
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3

Undergrad Time evolution of an expectation value

  • jaurandt
  • · Replies 12 ·
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12

Undergrad Measuring the number of waves in photon wave packets

  • exmarine
  • · Replies 1 ·
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1

Insights 9 Reasons Quantum Mechanics is Incomplete - Comments

  • Demystifier
  • · Replies 118 ·
4
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118

Undergrad What is "to the first order in H"?

  • Haorong Wu
  • · Replies 8 ·
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8

Undergrad Does quantum gravity blur the inverse square law at extreme distances?

  • sderamus
  • · Replies 3 ·
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3

Undergrad Is quantum mechanics deterministic if measurement effects occur naturally?

  • Pleonasm
  • · Replies 30 ·
2
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30

Undergrad Can a single photon decay into three photons via QED?

  • maline
  • · Replies 22 ·
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22

Undergrad Why no position operator for photon?

  • LarryS
  • · Replies 35 ·
2
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35

Undergrad Single ket for a product of two wave functions

  • Amentia
  • · Replies 5 ·
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5

Undergrad Doesn't the atom in ground state radiate?

  • thaiqi
  • · Replies 3 ·
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3

Undergrad Confusion on binding energy and ionization energy.

  • Cedric Chia
  • · Replies 3 ·
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3

Graduate Can we have a proton and an antiproton in the 1^S_0 atomic orbital

  • Jamiemma1995
  • · Replies 2 ·
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2

Undergrad Which-path info exists = deterministic context?

  • CHOP
  • · Replies 29 ·
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29

High School Is quantum superposition the same as regular superposition in physics?

  • Bianca Meske
  • · Replies 1 ·
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1

Undergrad Clarifying causes of correlations

  • vanhees71
  • · Replies 13 ·
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13

High School Particle properties conclusion from no-slit diffraction

  • roineust
  • · Replies 3 ·
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3

High School How do I explain quantum superposition?

  • Bianca Meske
  • · Replies 4 ·
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4

Undergrad Taylor expanding 1D scattering coefficient integral around k₀

  • WWCY
  • · Replies 6 ·
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6

Undergrad Locality and Wave Function Collapse Implications

  • The Head
  • · Replies 8 ·
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8

Undergrad Non-degeneracy of the quantum harmonic oscillator spectrum

  • Lebnm
  • · Replies 3 ·
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3

Undergrad Particle in a box experiment confirmation

  • ftr
  • · Replies 6 ·
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6

Graduate Why must pilot-wave mechanics be stochastic on a discrete spacetime lattice?

  • Ali Lavasani
  • · Replies 2 ·
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2

High School What makes photons from a laser cavity so directional?

  • intervoxel
  • · Replies 5 ·
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5

Insights Wigner's friend thought experiment

  • RUTA
  • · Replies 33 ·
2
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33

Undergrad Can Two Particle-in-a-Box Systems Interact to Affect Entropy?

  • WombatWithANuke
  • · Replies 3 ·
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3

Undergrad Very simple explanation of Wigner's friend needed

  • idea2000
  • · Replies 1 ·
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1

Insights A First Idea of Quantum Field Theory - 20 Part Series - Comments

  • Urs Schreiber
  • · Replies 9 ·
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9

Graduate Why does LS coupling apply to light atoms and jj coupling to heavy atoms?

  • bentzy
  • · Replies 6 ·
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6

Undergrad Two identical spin 1/2 particles

  • Lebnm
  • · Replies 1 ·
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1

Graduate Path Integral Approach To Derive The KG Propagator

  • Woolyabyss
  • · Replies 4 ·
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4

Undergrad Trouble with cubical cavity radiation

  • GhostLoveScore
  • · Replies 3 ·
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3

Undergrad New book on the foundations of quantum mechanics

  • ttn
  • · Replies 14 ·
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14

High School Taking Quantum Computers into Space

  • happyhacker
  • · Replies 13 ·
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13

Undergrad Double slit interactive detector

  • CHOP
  • · Replies 3 ·
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3

Undergrad Calculating the number of energy states using momentum space

  • JohnnyGui
  • · Replies 153 ·
6
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153

Undergrad Divergent vacuum uncertainty of fields in QFT, how to resolve?

  • HomogenousCow
  • · Replies 18 ·
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18

Undergrad Confusion about the Concept of Operators

  • jdou86
  • · Replies 14 ·
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14

Undergrad Space is discrete or continuous?

  • Philipsmett
  • · Replies 2 ·
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2

High School Is Born's rule really verified?

  • Dimosthenis76
  • · Replies 14 ·
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14

Undergrad How to quantum mechanically describe the photon?

  • Somali_Physicist
  • · Replies 14 ·
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14

High School Are there unverifiable assertions about probabilities

  • jk22
  • · Replies 4 ·
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4

Undergrad Does String Theory Justifiably Extend Gravitational Laws to Sub-Planck Lengths?

  • john t
  • · Replies 1 ·
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1

Undergrad Normalisation constant for identical particles

  • WWCY
  • · Replies 1 ·
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1

High School Why is L=2 not acceptable for carbon according to Hund's second rule?

  • Haorong Wu
  • · Replies 3 ·
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3

Undergrad Does Quantum Mechanics Suggest a Conservation of Possibilities?

  • entropy1
  • · Replies 1 ·
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1

Undergrad The Planck length and string theory

  • john t
  • · Replies 5 ·
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5

Undergrad Arrow of time and its reversal on a IBM quantum computer

  • andrew s 1905
  • · Replies 5 ·
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5

Undergrad Relation between spectral radiance and density of cavity

  • Jhordan
  • · Replies 7 ·
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7

Undergrad Does Grover's algorithm require knowing the answer to find it?

  • QComp
  • · Replies 13 ·
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13

Undergrad Will quantum computation lower energy requirements?

  • QGrav
  • · Replies 4 ·
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4

Undergrad Entanglement vs. Coherence in SPDC

  • Erik Ayer
  • · Replies 20 ·
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20

High School Delayed choice quantum communication - "Berlin riddle"

  • Bob Ziegler
  • · Replies 1 ·
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1

Undergrad Deriving the Maxwell tensor identity in Schwartz 8.23

  • dm4b
  • · Replies 3 ·
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3

Undergrad Why does the uncertainty principle drop the anti-commutator term?

  • dyn
  • · Replies 15 ·
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15

Undergrad Vacuum projection operator and normal ordering

  • "Don't panic!"
  • · Replies 19 ·
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19

Undergrad Solving Quantum Mechanics Integral Equation: How to Get from (1) to (2)?

  • physics bob
  • · Replies 4 ·
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4

Undergrad General solution to the Time-independent Schrödinger equation?

  • greswd
  • · Replies 8 ·
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8

Undergrad Against Collapse: A Mathematical Argument

  • Peter Morgan
  • · Replies 4 ·
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4

Graduate Has the 2-stage Stern-Gerlach experiment been performed?

  • Ali Lavasani
  • · Replies 2 ·
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2

Graduate Renormalization (Electron self energy)

  • Aleolomorfo
  • · Replies 4 ·
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4

Undergrad Fermi's golden rule 2E factors in QFT cross sections

  • tomdodd4598
  • · Replies 1 ·
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1

Undergrad The (quantum) world existing AND non-existing

  • entropy1
  • · Replies 1 ·
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1

Undergrad David Deutsch (1985) attempt to solve the incoherence problem

  • jxcs
  • · Replies 2 ·
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2

Undergrad What Is the Empty Space in the Double Slit Experiment's Interference Pattern?

  • Sdog
  • · Replies 7 ·
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7

Undergrad Weak interaction between electrons

  • Philipsmett
  • · Replies 5 ·
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5

Undergrad Spin matrices and Field transformations

  • Markus Kahn
  • · Replies 3 ·
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3

Undergrad Symmetries in quantum mechanics and the change of operators

  • Lebnm
  • · Replies 3 ·
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3

Graduate Haag's Theorem and the Poincare Group

  • DarMM
  • · Replies 29 ·
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29

Undergrad Why does a phonon bend away from gravity if it has positive mass?

  • snorkack
  • · Replies 15 ·
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15

High School Instant Quantum Communicator: Does Time Dilation Affect Voice?

  • KaiEris
  • · Replies 4 ·
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4

Insights A Classical View of the Qubit - Comments

  • A. Neumaier
  • · Replies 2 ·
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2

Undergrad Momentum of a stationary particle/wave?

  • Philip Land
  • · Replies 36 ·
2
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36

Undergrad Can the quantum eraser work without coincidence?

  • Erik Ayer
  • · Replies 1 ·
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1

Undergrad Should initial and final states be mixed states in the trace formula?

  • jk22
  • · Replies 2 ·
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2

High School Does the brain use quantum mechanics?

  • Demirci Kawa
  • · Replies 17 ·
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17

Graduate Concepts in a quantum synchronization setup

  • Danny Boy
  • · Replies 1 ·
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1

Undergrad How can one know the initial state from measurements?

  • pellman
  • · Replies 4 ·
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4

Graduate Multiverse vs Ugliverse vs Quantum Monism

  • jedishrfu
  • · Replies 3 ·
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3

Graduate Photon Spin and Polarization filters

  • PavanKumar
  • · Replies 5 ·
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5

Undergrad Newtonian Gravity Vs. Quantum Gravity

  • Quantum Physics
  • · Replies 1 ·
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1

High School Quantum entanglement mechanics

  • cHaRLie Bi0NiC
  • · Replies 3 ·
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3

Undergrad Continuous variable entanglement

  • WWCY
  • · Replies 1 ·
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1

Graduate Understanding Goldstone's Theorem Proof: Volume Limit and Commutator

  • Aleolomorfo
  • · Replies 1 ·
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1

Undergrad Difference between spin repulsion and electrostatic repulsion of an electron?

  • Philipsmett
  • · Replies 1 ·
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1

Graduate The relationship between random fields and quantum fields

  • Peter Morgan
  • · Replies 1 ·
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1

Undergrad Particle in a box and quantization of energy

  • Alan Ezra
  • · Replies 15 ·
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15

Undergrad The Classical Limit of Maxwell-Boltzmann Distribution

  • JohnnyGui
  • · Replies 2 ·
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2

Undergrad Ab Initio methods for chemical reactions?

  • jonjacson
  • · Replies 20 ·
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20

Undergrad Is it possible to detect an electrostatic field?

  • Philipsmett
  • · Replies 1 ·
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1

Undergrad Does wave superposition consume time?

  • LarryS
  • · Replies 1 ·
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1

Undergrad Why can't an electron be spinning?

  • Vampyr
  • · Replies 2 ·
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2

Undergrad Why are photoelectric measurements sensitive to surface properties?

  • Gerlan Silva
  • · Replies 3 ·
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3

High School Quantum field theory and the collapse of the wave function

  • Joao
  • · Replies 2 ·
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2

Undergrad Franson interferometer: Entanglement?

  • greypilgrim
  • · Replies 3 ·
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3

Graduate Frequency threshold in the photoelectric effect

  • Gerlan Silva
  • · Replies 10 ·
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10

Undergrad Superposition Analogy: Ceiling Fan Spin Beyond 15,000 RPM

  • ScienceMike33
  • · Replies 4 ·
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4

Undergrad Parity operator and a free particle on a circle

  • dyn
  • · Replies 57 ·
2
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57