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Quantum computing is right around the corner, but cooling is a problem. What are the options?

Neil Raden Profile picture for user Neil Raden March 17, 2020
Quantum computing is coming on fast, with potential use cases across industries. But nothing is happening at scale without a better cooling solution. One option on the table: synthetic diamonds.


Why would you be thinking about quantum computing? Yes, it may be two years or more before quantum computing will be widely available, but there are already quite a few organizations that are pressing ahead. I'll get into those use cases, but first - Let’s start with the basics:

Classical computers require built-in fans and other ways to dissipate heat, and quantum computers are no different. Instead of working with bits of information that can be either 0 or 1, as in a classical machine, a quantum computer relies on "qubits," which can be in both states simultaneously – called a superposition– thanks to the quirks of quantum mechanics. Those qubits must be shielded from all external noise, since the slightest interference will destroy the superposition, resulting in calculation errors. Well-isolated qubits heat up quickly, so keeping them cool is a challenge.

The current operating temperature of quantum computers is 0.015 Kelvin or -273C or -460F. That is the only way to slow down the movement of atoms, so a "qubit" can hold a value.

There have been some creative solutions proposed for this problem, such as the “nanofridge," which builds a circuit with an energy gap dividing two channels: a superconducting fast lane, where electrons can zip along with zero resistance, and a slow resistive (non-superconducting) lane. Only electrons with sufficient energy to jump across that gap can get to the superconductor highway; the rest are stuck in the slow lane. This has a cooling effect.

Just one problem though: The inventor, MikkoMöttönen, is confident enough in the eventual success that he has applied for a patent for the device. However, "Maybe in 10 to 15 years, this might be commercially useful,” he said. “It’s going to take some time, but I’m pretty sure we’ll get there."

Ten to fifteen years? As I noted, it may be a couple years before quantum computing will be widely available, but these use cases can't wait a decade for a proper cooling solution:

  • Supply-chain problems are complex. Optimizing dynamic supply chains is currently not feasible with available computing resources.
  • Insurance companies are under statutory obligations to provide a valuation of financial instruments to regulators such as bonds and derivatives, options, and risk on insurance products. The best can they do is to meet regulators' valuation requirements, which is not sufficient to value operational risk.
  • Drug discovery involves simulating molecules which is demanding with existing computing capabilities. The alternative, supercomputing, is the current but costly process. Some drug and biotech companies are already in the experimental phase.
  • Materials industries: Chemicals, Metals and Mining, Paper/Packaging, all of these industries are looking for better computation and optimization models for innovation and efficiency, not to mention better chips or batteries
  • Banking/Investment: Need better portfolio optimization, asset pricing, risk analysis, fraud detection, market predictions.
  • Blockchain relies on cryptographic methods, which may be open to constant attacks from the advancing capabilities of bad actors' newest technologies.
  • Industries counting on better batteries, chips or network architectures can explore quantum computing to simulate new possibilities or optimize existing structures.

An excellent, detailed report on the quantum computing ecosystem is: The Next Decade in Quantum Computing—and How to Play.

But the cooling problem must get sorted. It may be diamonds that finally solve some of the commercial and operational/cost issues in quantum computing: synthetic, also known as lab-grown diamonds.

The first synthetic diamond was grown by GE in 1954. It was an ugly little brown thing. By the '70s, GE and others were growing up to 1-carat off-color diamonds for industrial use. By the '90s, a company called Gemesis (renamed Pure Grown Diamonds) successfully created one-carat flawless diamonds graded ILA, meaning perfect. Today designer diamonds come in all sizes and colors: adding Boron to make them pink or nitrogen to make them yellow.

Diamonds have unique properties. They have high thermal conductivity (meaning they don't melt like silicon). The thermal conductivity of a pure diamond is the highest of any known solid. They are also an excellent electrical insulator. In its center, it has an impurity called an N-V center, where a carbon atom is replaced by a nitrogen atom leaving a gap where an unpaired electron circles the nitrogen gap and can be excited or polarized by a laser. When excited, the electron gives off a single photon leaving it in a reduced energy state. Somehow, and I admit I don’t completely understand this, the particle is placed into a quantum superposition. In quantum-speak, that means it can be two things, two values, two places at once, where it has both spin up and spin down. That is the essence of quantum computing, the creation of a "qubit," something that can be both 0 and 1 at the same time.

If that isn’t weird enough, there is the issue of “entanglement.” A microwave pulse can be directed at a pair of qubits, placing them both in the same state. But you can "entangle" them so that they are always in the same state. In other words, if you change the state of one of them, the other also changes, even if great distances separate them, a phenomenon Einstein dubbed, “spooky action at a distance.” Entangled photons don't need bulky equipment to keep them in their quantum state, and they can transmit quantum information across long distances.

At least in the theory of the predictive nature of entanglement, adding qubits explodes a quantum computer's computing power. In telecommunications, for example, entangled photons that span the traditional telecommunications spectrum have enormous potential for multi-channel quantum communication.

News Flash: Physicists have just demonstrated a 3-particle entanglement. This increases the capacity of quantum computing geometrically.

The cooling of qubits is the stumbling block. Diamonds seem to offer a solution, one that could quantum computing into the mainstream. The impurities in synthetic diamonds can be manipulated, and the state of od qubit can held at room temperature, unlike other potential quantum computing systems, and NV-center qubits (described above) are long-lived. There are still many issues to unravel to make quantum computers feasible, but today, unless you have a refrigerator at home that can operate at near absolute-zero, hang on to that laptop.

But doesn’t diamonds in computers sound expensive, flagrant, excessive? It begs the question, “What is anything worth?” Synthetic diamonds for jewelry are not as expensive as mined gems, but the price one pays at retail s burdened by the effect of monopoly, and so many intermediaries, distributors, jewelry companies, and retailers.

A recent book explored the value of fine things and explains the perceived value which only has a psychological basis.In the 1930s, De Beers, which had a monopoly on the world diamond market and too many for the weak demand, engaged the N. W. Ayers advertising agency realizing that diamonds were only sold to the very rich, while everyone else was buying cars and appliances. They created a market for diamond engagement rings and introduced the idea that a man should spend at least three month’s salary on a diamond for his betrothed.

And in classic selling of an idea, not a brand, they used their earworm taglines like “diamonds are forever.” These four iconic words have appeared in every single De Beers advertisement since 1948, and AdAge named it the #1 slogan of the century in 1999. Incidentally, diamonds aren’t forever. That diamond on your finger is slowly evaporating. OK, maybe close enough to forever: “It would take approximately the age of the universe - about 10 billion years - to see an observable distance."

The worldwide outrage over the Blood Diamond scandal is increasing supply and demand for fine jewelry applications of synthetic diamonds. If quantum computers take off, and a diamond-based architecture becomes a standard, it will spawn a synthetic diamond production boom, increasing supply and drastically lowering the cost, making it feasible.

Many thanks to my daughter, Aja Raden, an author, jeweler, and behavioral economist for her insights about the diamond trade.

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