De Broglie's proposal
  • Louis de Broglie (1892-1987) was a physicist famous for his quantum theories and his terrible haircut.
    • FUN FACT: It's pronounced "de Broy"
  • In 1923, he published several papers on light quanta and prepared his doctoral thesis, in which he whined that nobody has managed to prove whether light was a particle or a wave.
  • His stroke of genius came when he equated the energy of mass and the energy of a wave
(1)
\begin{equation} E = hf | E = mc^2 \end{equation}
(2)
\begin{align} \therefore hf = mc^2 \end{align}
(3)
\begin{align} mc = \frac{hf}{c} \end{align}
(4)
\begin{align} \therefore p = \frac{hf}{c} \end{align}

de Broglie's proposal

  • Through that he claimed that: "All matter has both particle and wavelike properties.
  • He developed the idea mathematically, linking all mass with a wavelength known as matter waves.
  • This wavelength can be found by:
(5)
\begin{align} \lambda = \frac{h}{mv} \end{align}
  • Where:
    • $\lambda$ is the "de Broglie wavelength (m)
    • h is Planck's constant ($6.626 \times 10^{-34}$
    • m is the mass of the object (kg)
    • v is the object's velocity ($ms^{-1}$)
  • de Broglie's proposal revolutionised modern physics and gave birth to the new field of quantum physics.
    • Quantum Physics was a field where the wave-particle duality of matter is focused on.
  • de Broglie's mathematical delvings and his proposal that electrons could be diffracted had great impact on the scientific community.
  • This new field of physics attracted other major scientists, like Pauli, Heisenberg, Schrodinger, Dirac and others.
  • These scientists developed a detailed theory known as quantum mechanics
    • Quantum mechanics describes a set of physical laws that apply to objects smaller than the size of an atom.
  • Also, it is shown later that De Broglie's allowed Bohr's stationary states to be adequately explained.