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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.

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Quantum Interpretations and Foundations

Seeking clarity on the physical definition of an observer
1.3K threads
Seeking clarity on the physical definition of an observer
High School QM randomness vs chaotic determinism?
  • lukephysics
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Undergrad Energy Non-Conservation in Quantum Mechanics
  • Coelum
  • · Replies 22 ·
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Undergrad Delayed choice quantum eraser setup with no beam splitter
  • Athraxin
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14
Undergrad How to prove that the L and S (of the total angular momentum commute?
  • Heidi
  • · Replies 17 ·
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High School Particle Movement in Quantum Mechanics
  • Islam Hassan
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Undergrad HUP for spin seems violated: 0 x sy > sz/2...?
  • JBlue
  • · Replies 4 ·
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4
Undergrad On a constructive method of quantum state preparation (Ballentine)
  • EE18
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Undergrad Trying to understand why electrons fill orbitals the way they do
  • physicurious
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10
High School Is there a probability in QM that an event happens at time t?
  • Heidi
  • · Replies 61 ·
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Undergrad General argument that entanglement can only be created locally
  • greypilgrim
  • · Replies 31 ·
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Undergrad What role does Quantum Mechanics play in a internal combustion engine?
  • obbeel
  • · Replies 6 ·
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6
High School Gravitrons vs Photons: how come light and gravity exist?
  • Any name will do
  • · Replies 16 ·
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16
Graduate In light of new evidence, what might be behind the Casimir Effect?
  • peterbb
  • · Replies 46 ·
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Undergrad What Is Bell's Theorem and Why Does It Matter?
  • golya
  • · Replies 3 ·
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Graduate Confused about going from relativistic to non-relativistic Hamilonian
  • Malamala
  • · Replies 1 ·
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Undergrad Solutions of the Bloch equations for MRT
  • Derbyshire
  • · Replies 6 ·
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6
High School The nature of anti-particles and anti-matter (a dilettante asks)
  • Any name will do
  • · Replies 8 ·
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Graduate Is the Fractional Quantum Hall Effect an emergent property?
  • Cato
  • · Replies 4 ·
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4
Undergrad How exactly does spooky action at a distance violate SRT?
  • greypilgrim
  • · Replies 18 ·
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18
Graduate K-point mesh and Monkhorst-Pack
  • ramana3797
  • · Replies 1 ·
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Graduate How can a 'Principle' produce a 'Force'?
  • sophiecentaur
  • · Replies 12 ·
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12
Graduate Method for delaying photon 140ms+ while maintaining entanglement?
  • criquant
  • · Replies 7 ·
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7
Undergrad Spontaneous Symmetry Breaking and quantum mechanics
  • arivero
  • · Replies 15 ·
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15
Undergrad Phenomena: Recent + Documented
  • Immer Tzaddi
  • · Replies 1 ·
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1
Graduate Importance of Densities in QFT
  • physwiz222
  • · Replies 1 ·
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Graduate Two Slit Interference Experiment Variations
  • Chas Tennis
  • · Replies 4 ·
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4
High School Double slit experiment, expensive gear?
  • rolnor
  • · Replies 49 ·
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Undergrad What does ## \psi^{*}\hat{H}\psi ## mean?
  • ConjugatedClanger
  • · Replies 9 ·
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9
Undergrad Can We Accurately Measure Momentum in the Lab?
  • dsaun777
  • · Replies 20 ·
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20
High School Extremely elementary questions about QM
  • okaythanksbud
  • · Replies 24 ·
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24
Graduate QFT S-matrix explanations are incomprehensible
  • jostpuur
  • · Replies 2 ·
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2
Graduate What exactly does 'Locality' in Gauge Theory mean?
  • The Tortoise-Man
  • · Replies 5 ·
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5
Graduate Potential between Photons via Delbruck Scattering
  • DuckAmuck
  • · Replies 5 ·
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5
Graduate What is the geometry of a gauge potential in the A-B experiment?
  • Anko
  • · Replies 2 ·
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2
High School Light, Photons, Waves, Particles: Wave-Particle Duality....
  • ISamson
  • · Replies 17 ·
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17
Undergrad Double slit as a function of time
  • dom_quixote
  • · Replies 9 ·
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9
Graduate Proving BF action is a difference of Chern-Simons actions
  • StarWombat
  • · Replies 0 ·
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Undergrad Some questions about this vintage periodic table
  • jmatt
  • · Replies 10 ·
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10
High School What happens to excess energy when an electron gets excited by light?
  • Richard2001
  • · Replies 7 ·
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7
Graduate How to derive the quantum detailed balance condition?
  • lsdragon
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Undergrad Can anyone explain me this quantum entanglement experiment
  • James2018
  • · Replies 4 ·
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4
Graduate Why does the description of a composite system involve a tensor product?
  • prabin
  • · Replies 2 ·
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2
Graduate Ground state calculation with a time averaged wave function
  • hilbert2
  • · Replies 2 ·
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2
Undergrad Photon Entanglement: Identifying & Using an Entangled Pair
  • RobbyQ
  • · Replies 4 ·
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4
Undergrad Confusion Regarding a Spectral Decomposition
  • ARoyC
  • · Replies 6 ·
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6
Undergrad Can we now explain the Fine Structure Constant?
  • RobbyQ
  • · Replies 5 ·
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5
Undergrad Do EM waves have negative frequency inside negative-index materials?
  • jeast
  • · Replies 4 ·
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4
Undergrad How can I model squeezed states in 3D optical modelling software?
  • Sciencemaster
  • · Replies 1 ·
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1
Undergrad Confusions I have regarding Measurements in Quantum Mechanics
  • ARoyC
  • · Replies 11 ·
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11
Undergrad How Do Gauge and Phase Symmetries Differ in Quantum Systems?
  • DrDu
  • · Replies 6 ·
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6
High School Interferometry: Photons Needed for Interference Pattern
  • Bob8102
  • · Replies 3 ·
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3
Graduate Anti-symmetric tensor question
  • DuckAmuck
  • · Replies 6 ·
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6
Undergrad Where do the vibrational modes of molecules come from?
  • asphy
  • · Replies 2 ·
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Undergrad How is the Schrodinger equation related to the Heisenberg equation?
  • Thamyres MARTINS
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Graduate Why Can't I Derive Eq.(7) from Phys.Lett.B Vol.755?
  • PRB147
  • · Replies 8 ·
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8
Undergrad Is photon energy negative in a negative-index metamaterial?
  • jeast
  • · Replies 11 ·
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11
Undergrad Force carrier particle trajectories and warped spacetime
  • jaketodd
  • · Replies 2 ·
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2
Undergrad Do Two Photons in a Radiative Cascade Exhibit Directional Correlation?
  • Clovis
  • · Replies 14 ·
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14
Undergrad The speed of forces, and applying relativity to force carriers
  • jaketodd
  • · Replies 7 ·
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7
Undergrad Callan-Symanzik equation for Effective Potential
  • thatboi
  • · Replies 1 ·
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1
Undergrad Quantum Circuit Confusion On Time Evolution
  • thatboi
  • · Replies 1 ·
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Undergrad Can the Lieb-Robinson Bound be Intuited from the Taylor Series of an Operator?
  • thatboi
  • · Replies 1 ·
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High School What is the nature of de Broglie matter wave? Is it longitudian or transverse?
  • nohtha
  • · Replies 8 ·
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8
Undergrad Interpreting Unitary Time Evolution
  • thatboi
  • · Replies 10 ·
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10
Undergrad Generating Entangled Electron Pairs
  • RobbyQ
  • · Replies 6 ·
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6
Undergrad A hurdle in quantum computing I've never been able to figure out
  • jaketodd
  • · Replies 26 ·
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Undergrad Quantum Mechanics vs Einstein: Light Btwn Black Holes, Double Slit Experiment
  • namelessuser
  • · Replies 3 ·
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3
Undergrad Is there a Crookes radiometer device with photoelectric effect?
  • jonjacson
  • · Replies 1 ·
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1
Undergrad Entanglement may reveal more about black holes? ...Even micro ones!
  • jaketodd
  • · Replies 4 ·
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4
Undergrad What is the limit in size that two particles/objects can be entangled?
  • jaketodd
  • · Replies 5 ·
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5
High School Is it possible to get the photoelectric effect in red color frequency?
  • Renandornelles
  • · Replies 11 ·
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11
Undergrad Spectroscopy: vibronic and rotational transitions
  • pisluca99
  • · Replies 1 ·
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1
Undergrad Antisymmetrizing a Factorized Polynomial Vanishes?
  • thatboi
  • · Replies 0 ·
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0
Undergrad Is there a generator of entangled photons with fixed polarization?
  • prokopcio
  • · Replies 11 ·
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11
Undergrad Clarification required for some equations in the formulation of ideal Bose gas
  • Wrichik Basu
  • · Replies 2 ·
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2
Graduate Identity with Gamma matrices and four-vector contractions
  • Francisco Alegria
  • · Replies 2 ·
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2
Undergrad Time dependence of operators in the Schrödinger picture
  • The Tortoise-Man
  • · Replies 5 ·
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5
Undergrad Help with a derivation from a paper (diatomic molecular potential)
  • Malamala
  • · Replies 2 ·
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2
Undergrad Singlet Halperin State Construction
  • thatboi
  • · Replies 0 ·
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0
Undergrad What is a False Vacuum? Understanding its Properties and Energy Differences
  • KurtLudwig
  • · Replies 10 ·
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10
Undergrad Hawking's latest contribution, is this an implication?
  • jaketodd
  • · Replies 10 ·
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10
High School What Distinguishes Wavefunction from Superposition in Photon Behavior?
  • syfry
  • · Replies 27 ·
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27
High School Does Wavelength Affect Uncertainty in Macroscopic Objects?
  • John Constantine
  • · Replies 11 ·
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11
Graduate Number of particles in canonical ensemble
  • Demystifier
  • · Replies 9 ·
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9
Undergrad JC Model in Python: Advice & Feedback Needed - Jon Poplett
  • JonPoplett
  • · Replies 2 ·
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2
Undergrad Emission Spectrum & Energy: Exciting Hydrogen Vapor
  • pisluca99
  • · Replies 3 ·
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3
Undergrad The Hamiltonian elements in Anderson dimer
  • hokhani
  • · Replies 4 ·
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4
Undergrad Two-photon Stimulated Raman Transitions
  • Nijiro
  • · Replies 2 ·
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2
Graduate What is this unitary invariant?
  • Heidi
  • · Replies 3 ·
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3
Undergrad How Does a Photon Interfere in an Experiment with Less Than One Photon?
  • Grelbr42
  • · Replies 14 ·
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14
High School Device that detects if someone is looking at the device?
  • Syamsu
  • · Replies 23 ·
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23
Undergrad Instability of hydrogen ground state if the time-reversal operator is unitary
  • ergospherical
  • · Replies 2 ·
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2
High School Examples of less popular pairs of physical properties with uncertainty (HUP)
  • syfry
  • · Replies 12 ·
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12
Graduate Real vs complex spherical harmonics for hexagonal symmetry
  • Junaidjami
  • · Replies 2 ·
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2
Undergrad Hossenfelder: Delayed Choice Quantum Eraser, Debunked?
  • Halc
  • · Replies 3 ·
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3
Undergrad Can Operators Have Multiple Partial Derivatives in Quantum Mechanics?
  • Happiness
  • · Replies 7 ·
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7
Undergrad Fermi energy for a Fermion gas with a multiplicity function ##g_n##
  • phos19
  • · Replies 1 ·
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1
Undergrad Physical meaning of two independent, non-interacting parts
  • vibhuav
  • · Replies 3 ·
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3
Undergrad What do you need to establish that spin is conserved?
  • Old Person
  • · Replies 3 ·
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3
Graduate Relativistically invariant 2-body phase space integral
  • George Wu
  • · Replies 3 ·
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3