Advances in Semi-Conductors: Quantum Mechanics (Part VI)
Here are the goals of this series of posts:
1. Outline the major events that formed this branch of physics
2. Describe in, simple words, the fundamental main ideas of Quantum Mechanics
3. Understand the essence of quantum computing
4. Understand aspects of current research into quantum technologies
Here’s an overview of my series of posts on Quantum Mechanics. I’ll publish these once a week beginning on the 12th of August.
1. The Historical Beginnings
2. James Bond teaches you uncertainty, entanglement, and interference
3. What is the probability that you’ll learn a bit about probability, quantum computing, qubit, polarization, and psi? 100%!
4. If Quantum Physics is Real, is Reality Real? What Jaden Smith didn’t tell you about the reality of our world (and the quantum physics of what’s real)
5. What is a quantum computer? A (fuller) introduction to Quantum Computing
6. Ongoing Quantum Research #1 (quantum semi-conductors and you) (this one right here)
QUANTUM MECHANICS PART VI
There are three great reasons to consider quantum computers as a worthwhile future technology:
- Quantum Computers can solve certain problems faster than any classical computer
- Our natural world is founded from quantum mechanics. We need quantum computers to simulate these fine particle interactions; a quantum a computer could do so at greater speeds.
- Quantum computers have reversible computations and therefore could consume less energy than standard computers**
**being that the cooling of the computer is eventually reduced.
The Challenges of Engineering Quantum Computers
To allow for superposition and entanglement requires a very delicate approach. These states are incredibly fragile. We explored “error-correction” as a step in the whole process of quantum computation. Extra qubits (whose purpose is track errors down in other qubits through entanglement) would report to scientists which errors have occurred. So error correction is definitely a challenge in making quantum computers.
Recent Developments
Quantum Emitters
The power of the atom. If one could replicate the well-isolated system of the atom with the precision of a quantum computer, one would have a reliable and feasable quantum system. A quantum computer needs to have an environment free from disturbances of any kind otherwise this delicate system would be prone to errors. For example, if it wasn’t isolated then quantum information would leak away (“decohere,” which means turn from quantum mechanical information to classical information, i.e. be no longer in a superposition or entangled state as a result of the environment). As a side note, no system is void of decoherence, but many research groups are trying to optimize quantum information transfer using cutting edge materials.
One solution? Nitrogen-Vacancy (NV) centers in diamond. This material, of the very smallest of sizes, has atom-like properties. They have long-lasting spin quantum states (so quantum information can be stored in a superposition for a while allowing for more computations to be had) and they allow for the easy transition of molecular energy states to change while absorbing or releasing electromagnetic radiation. This is called “optical radiation”. But wait! There’s more! NV centers could be a medium for quantum systems to reduce their decoherence.
These NV centers also allow for fast control using electricity or magnetism with the appropriate wiring. This is important because one could manage their quantum device in a multitude of ways.
Controlling and Reading Single Electron and Nuclear Spins
Spins in semiconductors and insulators can be disturbed. This could create an error in a quantum computer by affecting quantum states. However common causes of spin disturbances (in the crystalline structure of silicon in a typical semiconductor and insulator, nuclei tend to be magnetic) are often weak in NV Centers in Diamond. In effect, NV Centers in Diamond allow for spin quantum coherence times to increase. In simple English, this means that, if quantum coherence is the ability for waves to interfere with each other, then this wave interference is sustained in a good way to keep the probabilities of quantum states high and remove the naughty effects of magnetic and nuclear spins.
But magnetic and nuclear spins aren’t always naughty — in fact, if used correctly, spin can be generated by using an electric field instead of a magnetic field. This would be easier to fabricate and more feasible in a device. One cutting edge research group looking into how to manipulate spins in semiconductors is the Lee Bassett Lab under at the University of Pennsylvania who is an expert on it.
The Main Point?
Researching semi-conductors will help spin quantum computation around! In fact, researching more into the quantum world will help advance our world light years.
As I mentioned in the beginning of this series, understanding quantum mechanics allows us to see its interdisciplinary applications. From Quantum Computing to the Uncertainty Principle to the Double Split Experiment to Bohr, we’ve seen how cool Quantum Mechanics is.
I hope you consider reading the sources I’ve used throughout these posts to understand the field further and become an expert on it.
Stephen Hawking’s A Brief History of Time, Carlo Rovelli’s Reality is Not What It Seems, and Bub’s Bananaworld all proved essential to the development of this blog piece. I cannot recommend Dr. Raymer’s Quantum Physics: What Everyone Needs to Know more too — it is a great introduction on the subject and I enjoyed reading it thoroughly. I have synthesized, condensed, explored, and expanded upon their ideas into what is hopefully a coherent ultimate documentation of what these bright thinkers have brilliantly communicated. Some of their explanations and/or analogies have been re-purposed here due to their educational significance.
