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

Undergrad Struggling with one step to show quantum operator equality

  • troglodyte
  • · Replies 2 ·
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Graduate Ground state energy of a particle-in-a-box in coordinate scaling

  • hilbert2
  • · Replies 4 ·
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4

Graduate What is the cause of radioactive decay?

  • Dukon
  • · Replies 4 ·
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4

Undergrad Why does a non-convergent operator series create a paradox in Shankar's exercise?

  • Nitram
  • · Replies 14 ·
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14

Undergrad What happened to the spatial degrees of freedom for the second particle?

  • sophiatev
  • · Replies 1 ·
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1

Undergrad Does a quantum laser pointer show the double-slit experiment?

  • Benplace
  • · Replies 2 ·
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2

Undergrad QED on electromagnetic interactions in atoms

  • WWCY
  • · Replies 9 ·
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9

Undergrad Is it possible for non-spherical atomic orbitals to have spherical symmetry?

  • hokhani
  • · Replies 8 ·
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8

Graduate Contribution of vacuum fluctuation to the self-energy of the electron

  • yztsz
  • · Replies 1 ·
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1

Graduate Hartle-Hawking sum over all possible metrics?

  • Suekdccia
  • · Replies 1 ·
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1

Undergrad Measuring all three spin components simultaneously

  • Mr J
  • · Replies 1 ·
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Undergrad Understanding how to get the unpolarized cross-sections

  • JD_PM
  • · Replies 5 ·
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5

Undergrad Maximum violation of Bell's Inequalities?

  • john taylor
  • · Replies 7 ·
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7

Graduate Can Quantum Mechanics Calculate the Frequency of an Atomic Clock?

  • Bruce Harvey
  • · Replies 4 ·
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4

High School Bell's theorem, QFT, and the Relativity of Simultaneity

  • Lynch101
  • · Replies 64 ·
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Graduate Quantum Period is Compression Robust

  • Botsina
  • · Replies 1 ·
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Graduate Positive polarity of a retarded Green's function's imaginary part

  • gonadas91
  • · Replies 7 ·
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7

Undergrad Seeking better explanation of some quantum stats formulae

  • SamRoss
  • · Replies 3 ·
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3

Graduate Question: Unambiguous discrimination between two non-orthogonal states

  • PabloArteaga
  • · Replies 4 ·
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4

Undergrad Feynman's Lectures volume III (Ch:8) -- Resolution of vector states

  • Ishika_96_sparkles
  • · Replies 4 ·
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4

Undergrad Partition function of quantum mechanics

  • PGaccount
  • · Replies 2 ·
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2

Undergrad Clebsch–Gordan coefficients: An Identity

  • victor01
  • · Replies 3 ·
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3

High School Can replaced electrons with copied properties show interference?

  • borib
  • · Replies 5 ·
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5

Undergrad Probability of finding a particle in a 1-D box max. at centre?

  • Apashanka
  • · Replies 1 ·
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1

High School What happens when a photon reflects in a gap smaller than its wavelength?

  • Elbraido
  • · Replies 4 ·
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4

Undergrad Quantum Field Operators for Bosons

  • knowwhatyoudontknow
  • · Replies 4 ·
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4

High School Notation <x|s> in Feynman Lectures III 3-1: inner product or Green function?

  • anuttarasammyak
  • · Replies 2 ·
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2

High School Why are protons allowed in the nucleus?

  • Andrew Wright
  • · Replies 32 ·
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32

High School Uncertainty versus impossibility of measurement

  • SamRoss
  • · Replies 48 ·
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Undergrad Can the spin cause the collapse?

  • forofo
  • · Replies 1 ·
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1

Graduate Should tensor sum be used in matrix mechanics?

  • jk22
  • · Replies 5 ·
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5

Undergrad Many-worlds simulation program in C#

  • ShadownightPrograms
  • · Replies 5 ·
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5

Undergrad Invariance of a system under symmetry operations

  • sophiatev
  • · Replies 14 ·
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14

High School Virtual Particles are not Dark Matter?

  • HexHammer
  • · Replies 9 ·
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9

Undergrad Why eigenstates of L² aren't eigenstates of Lx

  • Apashanka
  • · Replies 14 ·
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14

Graduate Understanding how to derive the differential cross-section formula

  • JD_PM
  • · Replies 11 ·
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11

Undergrad The period-finding circuit for Shor's algorithm

  • tomdodd4598
  • · Replies 3 ·
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3

High School What Is the Occurrence Rate of Path Integral in a Photon Double-Slit Experiment?

  • HexHammer
  • · Replies 6 ·
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6

Graduate Off-diagonal elements in a density matrix

  • CarvalhoGD
  • · Replies 1 ·
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Graduate Relation between Dirac's equation density matrix and current with spin

  • forofo
  • · Replies 1 ·
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1

Insights Clarifying Common Issues with Indistinguishable Particles

  • A. Neumaier
  • · Replies 17 ·
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17

Undergrad Fermi's Golden Rule and the S-matrix

  • tomdodd4598
  • · Replies 5 ·
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5

Undergrad Could Planck-Einstein relation be applied to matter waves?

  • Haorong Wu
  • · Replies 4 ·
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4

Graduate Zero-point Energy Contribution Below the Planck energy cutoff

  • InconspicuousUnicorn
  • · Replies 1 ·
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1

Undergrad Relating photon polarization vectors to helicity eigenstates

  • PeroK
  • · Replies 9 ·
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9

Undergrad Could Quantum Physics explain the singularity in a Black Hole?

  • zuz
  • · Replies 6 ·
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6

Graduate 30-day Topological Quantum challenge

  • Replusz
  • · Replies 2 ·
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2

High School Question about squares of operators

  • etotheipi
  • · Replies 17 ·
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17

Undergrad Can we predict Bob's spin measurement if we know Alice's earlier result?

  • entropy1
  • · Replies 38 ·
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Undergrad Photon Interaction with Environment at Long Range

  • Another
  • · Replies 1 ·
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Undergrad Obtaining the Dirac function from field operator commutation

  • abivz
  • · Replies 2 ·
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2

High School Is Inverse Compton Scattering Related to the Doppler Effect?

  • Daniel Petka
  • · Replies 7 ·
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7

Undergrad Can atoms absorb photons with energy higher than transition energy?

  • Haorong Wu
  • · Replies 4 ·
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4

Graduate Could the fields for the particles and forces have the same origin?

  • Brad12d3
  • · Replies 1 ·
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Undergrad QFT - Field operator commutation

  • abivz
  • · Replies 3 ·
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3

Undergrad Physical meaning of the highest root / weight

  • fresh_42
  • · Replies 53 ·
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Undergrad Making interference fringes visible with a wide laser beam using glass wedges

  • Erik Ayer
  • · Replies 8 ·
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8

Graduate Quantum Mechanic/wave function/junction condition

  • GreenTea09
  • · Replies 3 ·
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3

Undergrad Does a photon lose energy passing through double slits?

  • Davephaelon
  • · Replies 23 ·
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23

Insights Compton scattering of massive and massless particles

  • neilparker62
  • · Replies 1 ·
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1

Undergrad Perturbation Theory and Zeeman Splitting

  • aliens123
  • · Replies 14 ·
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14

Undergrad Visualising an alternative formulation of Planck's Radiation Law

  • TheBigDig
  • · Replies 8 ·
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8

Graduate Exclusion principle in Helium 3

  • EternalStudent
  • · Replies 9 ·
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9

High School Mapping between rules of classical vs QM probability?

  • etotheipi
  • · Replies 6 ·
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6

Undergrad Why is the observer effect not just an experimental limitation?

  • TJonline
  • · Replies 19 ·
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19

Undergrad How are quantum properties harnessed to solve computational problems?

  • expos4ever
  • · Replies 8 ·
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8

Graduate Steps from equation 3 to equation 4 in quantum field theory

  • Adwit
  • · Replies 4 ·
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4

Graduate Quantum physics and the theory of evolution

  • Adib Jihad
  • · Replies 2 ·
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2

Graduate Phonons as a quasiparticles in a quantum LHO

  • LagrangeEuler
  • · Replies 29 ·
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29

Undergrad Why is the term "fluctuations" objectionable?

  • nomadreid
  • · Replies 11 ·
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11

Graduate Fluctuation in terms of Hilbert space formalsm

  • cyberkatru
  • · Replies 1 ·
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1

Undergrad Why does my derivation give E = ½hω instead of E = hω?

  • SpaceNerdz
  • · Replies 3 ·
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3

Undergrad How does entanglement avoid causality violation across reference frames?

  • pixel
  • · Replies 11 ·
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11

Undergrad Parametric down-conversion and double-slits

  • rodd
  • · Replies 1 ·
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1

Undergrad Negative Energy -- Are QI/QEI's Real?

  • cgreeleybsu
  • · Replies 11 ·
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11

Undergrad Lithium Atom Ground State Radial Wavefunction

  • bob012345
  • · Replies 28 ·
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28

Undergrad Is Chemistry the same everywhere?

  • .Scott
  • · Replies 3 ·
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3

High School How much math is required to do QM?

  • entropy1
  • · Replies 19 ·
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19

Graduate Zero overlap between two-meson state and final state in meson decay

  • JD_PM
  • · Replies 10 ·
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10

Graduate Why do different regularization schemes give different answers?

  • QFT1995
  • · Replies 5 ·
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5

High School How can the annihilation operator for photons be realized experimentally?

  • jeremyfiennes
  • · Replies 33 ·
2
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33

Undergrad Is it possible to explain Quantum tunneling with the HUP?

  • Nam Jeong Woo
  • · Replies 3 ·
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3

Graduate Why Is the Path Integral W[J] a Vacuum-to-Vacuum Amplitude?

  • PGaccount
  • · Replies 4 ·
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4

Undergrad Why do potential well boundaries use different inequality signs?

  • DrinkanDerive
  • · Replies 3 ·
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3

Undergrad Number of qubits required for Shor's algorithm to factor a number < 2^n

  • tomdodd4598
  • · Replies 2 ·
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2

Undergrad Thermal photons emission inside a material

  • Johnny5454
  • · Replies 3 ·
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3

Undergrad Vertex function, quantum action

  • The black vegetable
  • · Replies 2 ·
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2

Undergrad Finding matrices of perturbation using creation/annihilation operators

  • Keru
  • · Replies 3 ·
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3

High School Measuring entangled photons in different polarization bases

  • StevieTNZ
  • · Replies 3 ·
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3

Graduate Bremsstrahlung single photon or spectrum

  • gjj
  • · Replies 1 ·
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1

Undergrad Accuracy of the Density of States

  • JohnnyGui
  • · Replies 3 ·
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3

Graduate Coherent states: Orthonormal set? Overcomplete basis?

  • LagrangeEuler
  • · Replies 1 ·
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1

High School Ionization energy and energy levels

  • ilovepudding
  • · Replies 11 ·
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11

Undergrad Group Theory Appearing in Griffith's Elementary Particles (2nd Ed.)

  • Jdeloz828
  • · Replies 20 ·
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20

Graduate How ‘spooky’ is quantum physics? The answer could be incalculable

  • Demystifier
  • · Replies 24 ·
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24

Undergrad Why perturbation theory uses power series?

  • Phylosopher
  • · Replies 13 ·
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13

Undergrad Splitting of a one-particle wave function

  • Spacetime walker
  • · Replies 15 ·
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15

Graduate Why is the quantum Fisher information useful in quantum metrology?

  • jamie.j1989
  • · Replies 1 ·
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1

High School What's the exact point about time travel?

  • Benjamin_harsh
  • · Replies 6 ·
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6

Undergrad (Baby QM) Analytic Solution to the Infinite Square Well Problem

  • obstinatus
  • · Replies 2 ·
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2