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 Why are low-l states lower in energy than hydrogen while high-l states are nearly equal?

  • albertsmith
  • · Replies 5 ·
Replies
5

Graduate Adding Spin S1 and S2: A Puzzling Situation

  • dsr39
  • · Replies 4 ·
Replies
4

Graduate Wall Street Journal on Entanglement

  • DrChinese
  • · Replies 6 ·
Replies
6

Undergrad What are orthogonal wavefunctions?

  • lms_89
  • · Replies 3 ·
Replies
3

Graduate Can quantum entangled particles be used for faster-than-light communication?

  • Belzy
  • · Replies 5 ·
Replies
5

Graduate Product state and orthorgonality

  • KFC
  • · Replies 2 ·
Replies
2

Graduate The probe passes over an atom that is 3.20×10^2 nm tall.

  • albertsmith
  • · Replies 4 ·
Replies
4

Graduate Explaining the Hydrogen Atom Wave Function Paradox

  • albertsmith
  • · Replies 2 ·
Replies
2

Undergrad How does the uncertainty principle work?

  • vizzard
  • · Replies 9 ·
Replies
9

Graduate Preparing a certain superposition of electron states

  • thoughtgaze
  • · Replies 1 ·
Replies
1

Graduate Is the vacuum the same as a quantum vacuum?

  • redhedkangaro
  • · Replies 5 ·
Replies
5

High School How Are Math and Science Interconnected?

  • Matterwave
  • · Replies 4 ·
Replies
4

Graduate Commutators of Lorentz generators

  • nrqed
  • · Replies 5 ·
Replies
5

Graduate What's the Difference Between Quantum and Simple Harmonic Oscillators?

  • Thierry12
  • · Replies 2 ·
Replies
2

Graduate Do frequency operators predict measurement results in superposition states?

  • Fredrik
  • · Replies 5 ·
Replies
5

Graduate Can the Commutator of Charges in QFT be Calculated Using Different Times?

  • nrqed
  • · Replies 5 ·
Replies
5

Graduate Can Electrons Change Spin Sign?

  • o_neg
  • · Replies 4 ·
Replies
4

Graduate What is the precise definition of a bound state?

  • OB1
  • · Replies 5 ·
Replies
5

Graduate Understanding Dihydrogen Spin Isomers: An Overview and Explanation

  • splitringtail
  • · Replies 1 ·
Replies
1

Graduate Is a quantum system completely defined by its spectrum?

  • zetafunction
  • · Replies 2 ·
Replies
2

Graduate The Heisenberg Uncertainty Principle and velocity

  • hover
  • · Replies 1 ·
Replies
1

Graduate Is Quantum Metaphysics Bridging Science and Spirituality Beyond Space and Time?

  • redhedkangaro
  • · Replies 1 ·
Replies
1

Graduate Virtual Particles: Disproving Energy Conservation?

  • sandstorm
  • · Replies 2 ·
Replies
2

High School Atomic Vibration Speed: m/s Conversion

  • nocoolnames
  • · Replies 3 ·
Replies
3

Graduate Wave-particle duality and the photo-electric effect

  • NanakiXIII
  • · Replies 2 ·
Replies
2

Undergrad Property that gives electrons charge.

  • harkkam
  • · Replies 4 ·
Replies
4

Undergrad How an electron can re-radiate an electromagnetic wave

  • Thierry12
  • · Replies 4 ·
Replies
4

Graduate What Temperature Yields a 25% Population Probability at 7.00 eV in Copper?

  • viviane363
  • · Replies 1 ·
Replies
1

Graduate Could almost nothing really be something? Fourier series.

  • Spinnor
  • · Replies 6 ·
Replies
6

Graduate Why are KμKμ and KνKν terms absent from equation 3.11?

  • Fredrik
  • · Replies 2 ·
Replies
2

Graduate Critical temperature of a superconductor

  • viviane363
  • · Replies 6 ·
Replies
6

Graduate Double Slit Experiment Near The Singularity of a black hole

  • TomBombadil7
  • · Replies 4 ·
Replies
4

Graduate How come there is a particle with zero mass?

  • VodaVoda
  • · Replies 4 ·
Replies
4

Graduate Can fermion fields in QFT have dimensions other than 3/2 and 1/2?

  • fermi
  • · Replies 5 ·
Replies
5

Graduate Does the lowering operator give a|0> = |0> or a|0> = 0?

  • KFC
  • · Replies 10 ·
Replies
10

Graduate How to operate on product state?

  • KFC
  • · Replies 2 ·
Replies
2

Graduate How Does Anti-Commutativity Affect Grassmann Number Integration?

  • pellman
  • · Replies 4 ·
Replies
4

Graduate Is the Multi-Electron Wavefunction Truly Separable?

  • sokrates
  • · Replies 3 ·
Replies
3

Graduate Density Matrix in that DFT bible book

  • wolich22
  • · Replies 1 ·
Replies
1

Graduate Did the Quantum Field Exist at the Beginning of Time and Space?

  • redhedkangaro
  • · Replies 1 ·
Replies
1

Graduate Meaning of Expectation Values for <x^2> and <p^2> in Classical Mechanics

  • 13characters
  • · Replies 4 ·
Replies
4

Graduate Practical examples of superposition?

  • ayladarcy
  • · Replies 3 ·
Replies
3

Graduate Stationary schrodinger equation (basic problems regarding the basis being used)

  • roya
  • · Replies 3 ·
Replies
3

Graduate What Is the Root of Number Operator in Quantum Mechanics?

  • KFC
  • · Replies 1 ·
Replies
1

Graduate Second quantization and partial traces

  • ledamage
  • · Replies 3 ·
Replies
3

High School What is the difference between quantum mechanics and quantum physics?

  • dealrocker
  • · Replies 3 ·
Replies
3

Graduate Schrodinger Equations - wave propagation

  • krindik
  • · Replies 8 ·
Replies
8

Undergrad Why Does Quantum Mechanics Depend on Probability?

  • Pjpic
  • · Replies 1 ·
Replies
1

Graduate Formulation of Quantum Mechanics?

  • vizzard
  • · Replies 4 ·
Replies
4

Graduate Tunneling effect in Supercapacitors ?

  • Hans Peter
  • · Replies 1 ·
Replies
1

Graduate Can Quantum Mechanics Enlighten My Philosophical Ideas?

  • Cuban Lincoln
  • · Replies 7 ·
Replies
7

Graduate Systems with global phase invariance, 3D string?

  • Spinnor
  • · Replies 5 ·
Replies
5

Graduate Understanding Inelastic Collisions in Helium at Room Temperature

  • conway
  • · Replies 7 ·
Replies
7

Graduate Studying the Zeeman Effect on Molecules

  • hagopbul
  • · Replies 1 ·
Replies
1

Graduate What is the paradox in Planck's Law?

  • cmos
  • · Replies 62 ·
3
Replies
62

Undergrad Encryption v.s. quantum computers

  • ktoz
  • · Replies 26 ·
Replies
26

Undergrad Why is gold's color different from other metals?

  • dishku
  • · Replies 2 ·
Replies
2

Graduate SU(2) Spinor: Is Product of Two Scalar-Type Entity?

  • div curl F= 0
  • · Replies 1 ·
Replies
1

Graduate Why would entangled particles light years away need to be able to cancel?

  • Green Zach
  • · Replies 6 ·
Replies
6

Graduate Why does the infinite square well from -a to +a have cosine solutions?

  • mr_whisk
  • · Replies 3 ·
Replies
3

Graduate The smallest measurement device

  • Dmitry67
  • · Replies 8 ·
Replies
8

Undergrad Fourier transform and uncertainity principle

  • likephysics
  • · Replies 9 ·
Replies
9

Graduate Can photons collide with each other to produce new particles?

  • misnoma
  • · Replies 24 ·
Replies
24

Graduate Quantum-classical correspondence?

  • xylai
  • · Replies 41 ·
2
Replies
41

Graduate Harmonic Oscillator energy = WKB approximate energy why?

  • maverick280857
  • · Replies 3 ·
Replies
3

Graduate Solving KET-BRA Notation in OPW Solid State Physics

  • asifmumtaz
  • · Replies 2 ·
Replies
2

Graduate Why do molecules not fall apart under observation?

  • The thinker
  • · Replies 1 ·
Replies
1

Graduate Why do high energies correspond to small distances

  • RedX
  • · Replies 2 ·
Replies
2

Undergrad Does the Casimir Effect Occur in Space?

  • monty37
  • · Replies 1 ·
Replies
1

Graduate Do ghosts and gauge-fixing break gauge invariance in QFT?

  • RedX
  • · Replies 4 ·
Replies
4

Graduate Can you multiply two bra-ket expressions like < r | j >< a | j >?

  • chemstudent09
  • · Replies 8 ·
Replies
8

Graduate The Impact of Weak Realism on Bell's Theorem and Bohmian Interpretations

  • Ilja
  • · Replies 64 ·
3
Replies
64

Graduate Time Dependent Schrodinger Equation -> T(t) solution

  • karkas
  • · Replies 13 ·
Replies
13

Graduate Introductory books on quantum mechanics

  • mvillagra
  • · Replies 3 ·
Replies
3

Graduate Dirac's Coupling to an electromagnetic field and schroedingers

  • g.bashyam
  • · Replies 2 ·
Replies
2

Graduate Dot product of two pauli matrices

  • KFC
  • · Replies 5 ·
Replies
5

Graduate Why Do Photons Follow a Sine Wave Pattern Instead of Other Paths?

  • taylaron
  • · Replies 2 ·
Replies
2

Graduate U(1):?:SU(3) 1D:2D:3D harmonic oscillator.

  • Spinnor
  • · Replies 2 ·
Replies
2

Graduate 3-d harmonic oscillator and SU(3) - how to imagine it?

  • franoisbelfor
  • · Replies 4 ·
Replies
4

Graduate Energy Conservation in an expanded 1D box

  • dLo R6
  • · Replies 3 ·
Replies
3

Graduate Does quantum mechanical definition of momentum require movement ?

  • feynmann
  • · Replies 21 ·
Replies
21

Graduate Copenhagen interpretation of Quantum Theory

  • quddusaliquddus
  • · Replies 49 ·
2
Replies
49

Graduate Hydrogen spectrum hyperfine structure

  • edguy99
  • · Replies 1 ·
Replies
1

Graduate Classical counterpart of the quantum |nlm> states

  • wdlang
  • · Replies 1 ·
Replies
1

Graduate What Causes the Expansion of Our Universe?

  • saylem
  • · Replies 30 ·
2
Replies
30

Graduate Choice of source photon production in entanglement experiments

  • moving_on
  • · Replies 2 ·
Replies
2

Graduate Does the Hartree Approximation Ignore Electron Interactions?

  • chemstudent09
  • · Replies 1 ·
Replies
1

Graduate Explaining quantum coherence to non-physicists

  • Einstein Mcfly
  • · Replies 1 ·
Replies
1

Graduate Velocity, density, ect. : air : molecules spinor field :?:?

  • Spinnor
  • · Replies 3 ·
Replies
3

Graduate What exactly is an oscillator in quantum physical context?

  • Masna
  • · Replies 3 ·
Replies
3

Graduate Has entanglement in quantum physics been experimentally validated?

  • SDetection
  • · Replies 30 ·
2
Replies
30

Graduate Does quantized spacetime reduce the number of spatial dimensions?

  • theneedtoknow
  • · Replies 4 ·
Replies
4

Graduate Elementary Particles with Zero Spin?

  • LarryS
  • · Replies 1 ·
Replies
1

High School Drawbacks of bohr's model of atom

  • roshan2004
  • · Replies 1 ·
Replies
1

Graduate How do you transition from the QED Lagrangian to classical electrodynamics?

  • Ben Niehoff
  • · Replies 5 ·
Replies
5

Graduate Why No Decoherence in Double Slit Experiment?

  • Feeble Wonk
  • · Replies 7 ·
Replies
7

Undergrad Why the Rutherford model can't explain hydrogen line spectra

  • roshan2004
  • · Replies 22 ·
Replies
22

Graduate Does QCD need the Lambda parameter outside perturbation theory?

  • fermi
  • · Replies 4 ·
Replies
4

High School Converting frequency to energy with Planck's equation

  • Hertz
  • · Replies 5 ·
Replies
5

Graduate Wave propagation, +z or -z

  • sokrates
  • · Replies 1 ·
Replies
1