Way back in the early 's, physicists noticed that every element in the periodic table has a unique spectrum: if you get a vapor of atoms hot, they emit light at a smallish number of discrete frequencies, with a different pattern for every element. These "spectral lines" were quickly used to identify the composition of unknown materials, and even to discover the presence of previously unknown elements-- helium, for example, was first detected as a previously unknown spectral line in light from the Sun.
While this was undeniably effective, nobody could explain it until when Niels Bohr picked up on Planck's quantum idea which Einstein extended in and introduced the first quantum model of an atom. Bohr suggested that there are certain special states in which an electron can happily orbit the nucleus of an atom, and that atoms absorb and emit light only as they move between those states.
Vital Pieces of What Is Quantum Theory
The frequency of the light absorbed or emitted depends on the energy difference between states in the way introduced by Planck, thus giving a set of discrete frequencies for any particular atom. This was a radical idea, but it worked brilliantly to explain the spectrum of light emitted by hydrogen, and also the x-rays emitted by a wide range of elements, and quantum physics was off to the races.
While the modern picture of what's going on inside an atom is very different than Bohr's initial model, the core idea is the same: electrons move between the special states inside atoms by absorbing and emitting light of particular frequencies. This is the core idea behind fluorescent lighting: Inside a fluorescent bulb either long tube or CFL there's a little bit of mercury vapor that's excited into a plasma.
Mercury happens to emit light at frequencies that mostly fall in the visible spectrum in a way that can fool our eyes into thinking the light looks white. If you look at a fluorescent bulb through a cheap diffraction grating like you'll find in novelty glasses, you'll see a few distinct colored images of the bulb, where an incandescent bulb gives a continuous rainbow smear. So, any time you use fluorescent lights to light your home or office, you have quantum physics to thank for it.
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High angle shot of an unrecognizable young businesswoman working on her laptop in her home office. Computers : While Bohr's quantum model was undeniably useful, it didn't initially come with a physical reason as to why there should be special states for electrons within atoms. That didn't come for almost ten years, but once the idea got locked it, it turned out to be the basis for the most transformative technological revolution of the last century. The radical idea that provided a physical basis for Bohr's special energy states came from Louis de Broglie, a French Ph. He suggested that just as Planck and Einstein had introduced a particle-like nature for light waves where a beam of light can be thought of as a stream of "light quanta" each carrying one unit of energy for that frequency , there might be a corresponding wave-like behavior for particles like electrons.
If you give electrons a wavelength that depends on their momentum, you find that there are "standing wave" orbits where the electron wave completes an integer number of oscillations as it goes around the nucleus, and these have exactly the right energies to be Bohr's special states in hydrogen. This wave behavior is something that can be directly measured, and it quickly was in both the US and UK.
The wave nature of electrons profoundly changes our understanding of how they move through materials, leading to our modern understanding of energy bands and band gaps within materials. We can use this physics to control the electrical properties of semiconductors, and by sticking together bits of silicon with the exact right admixture of other elements, we can make tiny transistors that form the basic bits used to process digital information. So, every time you turn on your computer say, to read a blog post about quantum physics , you're exploiting the wave nature of electrons, and the unprecedented control of materials that allows.
It may not be the sexy kind of quantum computer, but every modern computer needs quantum physics to work properly. These are just a few of the ways that quantum physics shows up in the course of your everyday life. If you'd like to see these discussed in much more detail, along with several other topics that I may return to in later posts, you should check out my new book, Breakfast with Einstein , available now in the UK from Oneworld Publications and next week in the US from BenBella Books. Ships in 15 business days. Link Either by signing into your account or linking your membership details before your order is placed.
Description Table of Contents Product Details Click on the cover image above to read some pages of this book! Industry Reviews From the reviews: "This book is a modern textbook covering most aspects of the theory and recent developments. A, B, C to Probabilities. Expectation Values and Matrix Representations. Pure Ensembles and Mixtures 1.
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Polarization of Light: An Interlude. Self-Adjoint Operators and Their Spectra. Wigner's Theorem on Symmetry Transformations.
Probability, Conditional Probability and Measurement. Galilean Space-Time Coordinate Transformations. Successive Galilean Transformations and the Closed Path.
Quantum Theory: A Wide Spectrum
Quantum Galilean Transformations and Their Generators. The Transformation Function x p. Quantum Dynamics and Construction of Hamiltonians. Appendix to 2. Discrete Transformations: Parity and Time Reversal. Orbital Angular Momentum and Spin. Spinors and Arbitrary Spins.
What You Don’t Know About What Is Quantum Theory
Uncertainties, Localization and Stability. Boundedness of the Spectra of Hamiltonians From Below. Decay of Quantum Systems. Appendix to 3. Hamiltonians with Potentials Vanishing at Infinity. On Bound-States.
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Counting the Number of Eigenvalues. Appendix to 4. The Eigenvalue Problem and Supersymmetry. The Eigenvalue Problem. Matrix Elements of Finite Rotations. Orbital Angular Momentum.
https://hydtecosita.tk Addition of Angular Momenta. Explicit Expression for the Clebsch-Gordan Coefficients. Vector Operators. Tensor Operators. Combining Several Angular Momenta: 6-j and 9-j Symbols. The Harmonic Oscillator. The Fermi Oscillator. Coherent State of the Harmonic Oscillator.