Rise of quantum computers
End of the age of silicon
In 2019 and 2020 two groups announced that they had achieved quantum supremacy. A quantum computer, could decisively outperform an ordinary digital supercomputer on specific tasks.
Instead on computing on tiny transistors, quantum computers compute on the tiniest possible object, the atoms themselves.
Digital computers can never accurately calculate how atoms combine to create crucial chemical reactions, especially those that make life possible. A quantum computer, however, simultaneously analyzes all possible paths at the same time with lightning speed.
China and the U.S. are not the only ones using government funds to accelerate this technology. The U.K. government is now constructing the National Quantum Computing Centre.
Areas like chemistry, medicine, oil and gas, transportation, logistics, banking, pharmaceutical, and cybersecurity are ripe for major change.
Back in 2012 physicist John Preskill of the California Institute of Technology first coined the term “quantum supremacy”.
Computing on individual atoms, rather than wafers of silicon chips, was considered fiendishly difficult. The slightest vibration or noise can disturb dance of atoms in a quantum computing.
The rise of quantum computers is a sign that the Age of Silicon is gradually coming to a close. Moore’s law is already slowing down and may eventually come to a halt. This is because microchips are so compact that the thinnest layer of transistors is about twenty atoms across. When they reach about five atoms across, the location of the electron becomes uncertain, and they can leak out and short-circuit the chip or generate so much heat that the chips melt.
Richard Feynman in 1959 saw a different approach to digital information. ‘There’s plenty of room at the bottom’. Why not replace this sequence of 0s and1s with states of atoms, making an atomic computer. Atoms can carry much more information, not just bit, but a qubit. They are not only 1 or 0, depending on their spin and alignment with respect to magnetic field, but they can be 10% up and 90% of time down. The fact that, at the atomic level, objects can exist simultaneously in multiple states is called superposition. We also have entanglement, where qubits can interact with each other on a distance.
In order for quantum computers to work, atoms have to be arranged precisely so that they vibrate in unison, this is called coherence. So, they should operate in near absolute zero environment.
There are many areas where quantum computers can overtake conventional digital computers:
- Search engines. Quantum computers may be ablet to analyze a company’s finances in order to isolate the handful of factors that are preventing it from growing.
- Optimization. Once quantum computers have used search engines to identify the key factors in the data, the next question is how to adjust them to maximize certain factors, such as profit.
- Simulation. Quantum computers might also solve complex equations that are beyond the ability of digital computers. All of biology, medicine, and chemistry would be reduced to quantum mechanics.
- Merger of AI and quantum computers. AI excels at being able to learn from mistakes, so that it can perform increasingly difficult tasks.
The key bottleneck for the Solar Age is often overlooked; it is the battery. Quantum computers can attack the battery problem. Another crucial application of quantum computers might be to feed the world’s growing population. Can quantum computers solve a problem of efficient fertilizer production, creating a second Green Revolution. Another miracle of nature is photosynthesis, in which sunlight and carbon dioxide are turned into oxygen and glucose. The problem of converting light into sugar is a quantum mechanical problem. When we decipher the mechanisms at the molecular level, scientists will create new cures and therapies. The protein folding problem can also be tackled better with quantum computing.
End of the digital age
In 1901 first world computer was discovered in the Aegean Sea. It was a machine with fears, wheels, and strange inscriptions. The purpose of the world’s first computer was to simulate heavenly bodies. Simulation is one of our deepest human desires.
It wasn’t until the 1800s that interest in computers was gradually revived. English inventor and visionary Charles Babbage dream was to create the most advanced computing machine of his time. He was quite persuasive in recruiting eager followers. One of them was Lady Ada Lovelace. She was, in a sense, the world’s first programmer.
What Lovelace saw … was that number could represent entities other than quantity. And if those numbers represented other things, letters, musical notes, then the machine could manipulate symbols of which number was one instance, according to rules.
Instead of building increasingly complex adding machines like Babbage’s difference engine. Alan Turing eventually asked himself a different question: Is there a mathematical limit to what a mechanical computer can perform? In other words, can a computer prove everything?
Today. Turing machines are the foundation for all modern computers. Turing imagined an infinitely long tape, which contained a series of squares or cells. Inside each square, you could put a 0 or 1, or you leave it blank.
Turing reduced mathematics to a game: by systematically replacing 0 with 1 and vice versa, one could encode all of mathematics.
The work of Turing and others replaced the analog computer with a digital computer. Analog signals are exceedingly difficult to alter. But digital signals can be altered with the push of a button by using simple mathematical algorithms.
Turing’s work is based on something called determinism. The idea that the future is determined ahead of time. Determinism would be overthrown. In the same way that Godel and Turing helped show that mathematics is incomplete, perhaps computers of the future would have to deal with the fundamental uncertainty introduced by physics.
Rise of the quantum
Max Planck was one of the greatest revolutionaries of all time.
According to Newton, the universe was a clock. It was ticking away following his three laws of motion in a precise and predetermined way. This was called Newtonian determinism.
If you move a charged atom fast enough, it radiates electromagnetic radiation according to the laws of James Clerk Maxwell.
Using Newton’s theory applied to the atom, and using Maxwell’s theory of light, one can calculate the light emitted from a hot object.
But when the calculation is actually performed, disaster strikes. The energy emitted can become infinite at high frequencies, which is impossible. Planck tried to derive the Rayleigh-Jeans catastrophe. He supposed that the energy emitted from an atom could only be found in tiny discrete packs of energy, which are called quants.
Planck’s revolutionary insight meant that Newtonian mechanics was incomplete, and a new physics must emerge.
Planck wrote: “A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.”[1]
The man who explained the photoelectric effect was Albert Einstein, and he did it using Planck’s theory. Light hitting a metal, knocking out an electron and creating small electrical current.
In 1924, Louis de Broglie. If light can occur both as a particle and a wave, then why not matter? Perhaps electrons also possessed duality. If matter can act like a wave, his friend asked, then what is the equation that it must obey? Schrodinger set out to find the wave equation for electrons.
Chemistry has been reduced to physics.
If the electron was a wave, then what is waving? One
Max Born – matter consists of particles, but the probability of finding that particle is given by a wave. The new interpretation meant that you can only calculate probabilities, never certainties. You can only calculate likelihood of where particle was.
The uncertainty principle. Previously, mathematicians were forced to confront the incompleteness theorem, and now physicist had to confront the uncertainty principle. Physics, like mathematics, was somehow incomplete.
In the subatomic world, an electron can exist simultaneously as the sum of different states. Only after a measurement is made will the wave finally collapse and yield the correct answer. This is called the measurement problem.
While classically computers only sum over just 0s and 1s, quantum computers sum over all quantum states between 0 and 1.
In the microworld, things do not exist in definite states, but only as the sum of all possible states. Solipsism is the idea that philosophers like George Berkley believed in. It states that objects do not really exists unless you observe them.
Mathematician John von Neumann believed that there was an invisible “wall” that separated the microworld from the macroworld.
The universe was undeniably a quantum universe. Bohr said that anyone who is not shocked by the quantum theory does not understand it.
In Solvay Conference Bohr defended quantum theory against Einstein. Five years later, Einstein mounted his final counterattack with his students Boris Podolsky and Nathan Rosen. One unforeseen by product of this fateful challenge would be the quantum computer.
Information can travel instantly between coherent particles, but useful information that carries a message cannot go faster than light. Today this principle is called entanglement. Two coherent objects (vibrating in the same way) remain coherent even if separated by vast distances.
This has major implications for quantum computers.
Dawn of quantum computers
The transistor is perhaps the most important invention of the twentieth century.
Three physicists won the Nobel Prize in 1956 for the creation of this wonder device: John Bardeen, Walter Brattain and William Schockley. They used a new quantum form of matter called the semiconductor. Semiconductor can both carry and stop the flow of electrons. The transistor exploits this crucial property.
Transistor is created by first creating a template of the image of the circuits you want. Then you place template over the silicon wafer. Then you apply a beam of ultraviolet radiation onto the template, so the image is transferred onto the silicon wager. You then remove the template and add acid. The silicon chip is specially treated chemically so that, when you apply the acid, it burns the image you desire in the wafer.
As the width of the components of a silicon chip approaches the size of an atom, the Heisenberg uncertainty principle kicks in, and the electrons’ position become uncertain. In other words, all things must pass, including the Silicon Age. A new age may be dawning: the Quantum Age.
Richard Feynman realized that computers were becoming smaller and smaller. So he asked himself a simple question: How small can you make a computer. His speech at Caltech in 1959 anticipate the birth of a new science. His basic idea was simple: to create tiny machines that could “arrange the atoms the way we want”. “Nature isn’t classical, dammit, and if you want to make a simulation of nature, you’d better make it quantum mechanical.”
Feynman’s Path Integral is him rewriting the quantum theory in terms of the principle of least action. In this view, subatomic particles “sniff out” all possible paths. On each path he put a factor related to the action and Planck’s constant. Then he summed or integrated over all possible paths. This is now called the path integral approach, because you are adding up contributions from all the paths an object can take. He found he could derive the Schrodinger equation.
Photosynthesis, and hence life itself, may be a by-product of Feynman’s path integral approach.
David Deutsch helped make the foundation of quantum computers rigorous. By isolating the essence of how qubits are manipulated, he helped standardize work on quantum computers.
Hugh Everett. His proposal was daring and controversial. He said that you don’t need to collapse the wave, that each solution continues to exist in its own reality, producing, as the theory is known “many worlds”.
If your try to apply superposition to the entire universe, then you necessarily wind up with parallel universes, just as Everett predicted.
In quantum mechanics, everything is reduced to a probability.
Why are quantum computers so powerful? Because the electrons are simultaneously calculating in parallel universes. They are interacting and interfering with each other via entanglement.
All the bizarre features of the quantum theory that make quantum theory that make quantum computers possible:
- Superposition. Before you observe an object, it exists in many possible states.
- Entanglement. When two particles are coherent and your separate them, they can still influence each other.
- Sum over paths. When a particle moves between two points, it sums over all possible paths connecting these two points.
- Tunneling. When faced with a large energy barrier, normally a particle fails to penetrate it. But in quantum mechanics, there is a small but finite probability that you can “tunnel” or penetrate through the barrier.
The race is on
Some of the biggest names in Silicon Valley are now placing their bets on which horse will win this race.
Any quantum system that can superimpose states of 0s and 1s entangle them so that they can process this information can become a quantum computer.
Superconducting Quantum Computer. They have a great advantage: they can use off-the-shelf technology by the digital computer industry. But the slightest vibration or impurity can break the coherence of the circuits.
Ion Trap Quantum Computer. When you take an electrically neutral atom and strip off some electrons, you get a positively charged ion. Microwave or laser beams can hit these ions, flipping them and causing them to change state. Honeywell is one of the leading proponents of this model. Scaling is the problem here.
Photonic Quantum Computers. They exploit the fact that light can vibrate in different directions, that is, in polarized states. The number 0 or 1 can be represented by light vibrating in different polarized directions. They can be really big. But they can operate at room temperature.
Silicon Photonic Computers. PsiQuantum is the company behind it.
Topological Quantum Computers. The dark horse in this race is the Microsoft design, which uses topological processors.
D-Wave Quantum Computers. They excel in one area, optimization. They are using magnetic and electric fields.
Quantum computers and society
The origin of life
The origin of life is perhaps one of the greatest mysteries of all time.
Quantum computers are ideally suited for this problem and are now beginning to uncover some of the deepest secrets of life at the molecular level.
Using quantum mechanics, one can calculate the energy necessary to break the chemical bonds of methane, ammonia, etc., to create amino acids.
X-rays unlike visible light, can have a wavelength as small as atoms. Glancing at the X-ray photo of DNA taken by Rosalind Franklin, Crick and Watson saw a pattern that they recognized must be created by a double helix.
Walter Gilbert won a Nobel in 1980, he was one of the first to develop a rapid technique to read the DNA molecule, gene for gene.
Francis Collings uncovered the gene mutation responsible for cystic fibrosis.
Gilbert and Collins, in some sense, represent some of the stages in the development of Biotechnology:
- Stage One: Mapping the Genome
- Stage Two: Determining the Function of the Genes
- Stage Three: Modifying and Improving the Genome
DNA is believed to have originated around 3.7 billion years ago.
The quantum theory allows for several mechanisms to vastly accelerate a chemical process. We also know that enzymes can speed up chemical processes. Whirlwind advances in quantum computers are giving birth to new sciences called computational chemistry and quantum biology. Quantum computers are making it possible to create realistic models of molecules, allowing scientists the ability to see, atom for atom, nanoseconds by nanoseconds, how chemical reactions take place. Quantum computers are now at the point where they can begin to model the energetics and properties of small molecules.
The next target may be photosynthesis, one of the most important quantum processes on the planet.
Greening the world
If one day quantum computers can solve the secret of photosynthesis, then it would be possible to make photovoltaic cells with near-perfect efficiency, making the Solar Age a reality. We could also increase the yield from crops to feed a hungry planet.
By the 1950s, scientists pieced together what is called the Calvin cycle. But one step always eluded them. How do plants capture the energy of photons of light in the first place?
Many scientists believe photosynthesis is a quantum process. One theory is that journey of the exciton (energy vibration of the leaf caused by the photon of light that impacts chlorophyll) is made possible by path integrals. K. Birgitta Whaley thinks that the excitation effectively ‘picks’ the most efficient route … from a quantum menu of possible paths.
Quantum computers could play a decisive role in achieving carbon recycling.
If quantum computers provide the final step to creating artificial photosynthesis and the artificial leaf, it may open up entirely new industries that can provide new forms of efficient solar cells, alternate forms of crops, and new forms of photosynthesis.
Feeding the planet
Fritz Haber was the man who discovered how to make artificial fertilizers. No one has been able to improve upon the Haber-Bosch process for a hundred years because it is so complicated at the molecular level.
Back in 1798, Thomas Robert Malthus predicted that one day the population of the human race might exceed the food supply.
In nature, the fundamental energy source is found in a molecule called ATP. The key to understanding the secret of the ATP molecule is to analyze its structure. The molecule’s energy is stored in an electron located in the last phosphate group.
When analyzing the nitrogen-fixing process in plants, chemists discovered that twelve molecules of ATP are required to supply the energy to break open a single N2 molecule. Quantum computers may be able to help solve this riddle. The key is something called catalysis. The catalyst is called nitrogenase. One company investigating this ambitious project is Microsoft.
Energizing the world
Edison and Ford were betting on which energy source would power the future. Edison favored the electric battery, while Ford believed in gasoline.
Gasoline won, for now.
The weak link in the chain of renewable energy is storage – how you store energy for a rainy day. Battery power only grows when we discover new efficiencies or even new chemical compounds. Currently, it still uses chemical reactions that were known in the last century. Allesandro Volta built first battery in 1799.
The lithium-ion battery has an anode made of graphite, a cathode made of lithium cobalt oxide, and an electrolyte made of ether.
We need battery with an energy density approaching that of its fossil fuel rival. The lithium-air battery is one potential way to go. Its density is ten times of that of the lithium-ion battery.
Not surprisingly, the automotive industry is investing in quantum computers to see if a super battery might be designed using pure mathematics.
Quantum medicine
Quantum health
Antibiotics have been so effective and so often prescribed that now the germs are fighting back. There is an urgent need for a new generation of antibiotics that are cheap enough to justify their cost. It costs about 2 to 3 billion USD to develop a new class of antibiotics by standard methods.
Quantum computers might upend this process entirely and accelerate the search for new lifesaving drugs. This means reversing the order of the strategy: identify the mechanism, determine if it kills bacteria, test promising substance. Trying to discover new drugs by analyzing their molecular behavior can be a prime target for quantum computers.
Quantum computers can also help with testing vaccines and they can give us an early warning system to detect emerging viruses.
Gene editing and curing cancer
Cancer is not one disease at all, but thousands of different types of mutations in our genes. Cancer cells are ordinary cells that have forgotten how to die.
Analyzing odor is a proven diagnostic technique. Andreas Mershin of MIT is trying to create a “nano-nose”, which has microsensors capable of detecting cancers and other ailments, and then alerting you via your cell phone.
Quantum computers may be powerful enough to unravel, molecule for molecule, how the immune system does it magic.
Quantum computers can be used to identify and isolate complex genetic diseases, and CRISPR might be used to cure them.
List of some of the genetic diseases currently being treated by CRISPR:
- Cancer
- Sickle Cell Anemia
- AIDS
- Cystic fibrosis
- Huntington’s disease
One day, liquid biopsies may be able to detect cancer cells years to decades before tumors form. Quantum computers may also modify our immune system that would allow it to attack hundreds of different types of cancer.
AI and Quantum Computers
Can machines think? This was the question that dominated the historic 1956 Darmouth Conference. AI and quantum computers complement each other. AI has the ability to learn new, complex tasks, and quantum computers can provide the computational muscle it needs.
Mother Nature designs creatures that are pattern-seeking learning machines, using trial and error to navigate the world. This is bottom-up approach.
Learning machines or neural networks may eventually solve one of the most stubborn problems in AI: the “common-sense problem”.
AI deep learning systems are now tackling one of the greatest problems in all of biology and medicine: to decode the secret of protein molecules. Proteins are the workhorses of biology. At protein the shape is important. Function follows form.
X- ray crystallography has been the key to determining the shape of a protein molecule, but it is a long, tedious process.
By 2021 Deep Mind, announced that their AI program, called AlphaFold, had deciphered the rough structure of as astounding number of proteins: 350.000.
The frontiers of medicine, incurable diseases, may be the next battlefront for quantum computers.
Immortality
The oldest quest of all, stretching back to the earliest prehistory is the search for immortality.
Quantum computers may be able to create two kinds of immortality: biological and digital.
The physics of aging can be explained using the laws of thermodynamics, that is, the laws of heat. The Second Law says that in a closed system, chaos and decay always increase.
According to the Second Law, aging is primarily caused by the accumulation of errors at the molecular, genetic and cellular level.
Cell dies when it reaches the Hayflick limit. The Hayflick limit occurs because there is a cap, called a telomere, at the end of the chromosome, which gets shorter with each reproduction. It is also possible to “stop the clock”. There is an enzyme, called telomerase, which can prevent the telomeres from becoming increasingly short.
Quantum computers may be able to solve the mystery of how telomerase can cause a cell to become immortal but not cancerous.
Caloric restriction is one way to improve length of living. It does that by slowing down the oxidation process. This allows the body to repair the damage it causes naturally (inflammations).
Shinya Yamanaka is one of the authorities on stem cells. Can you reprogram an aging cell to become youthful again? Yes, under certain circumstances, there are four proteins (now called Yamanaka factors) that can perform the reprogramming process.
In the near future, most of the human population will have their genome sequenced and included in a giant global gene bank.
The key is that quantum computers will be able to attack the aging process in the arena in which it takes place: at the molecular level.
Modeling the world and the universe
Global warming
Quantum computers also hold immense potential from an environmental perspective. We need accurate assessments of the greenhouse effect, and how human activity is contributing to it.
Some alternative solutions to be used in the worst-case scenarios:
- Carbon sequestration. It cost money. This approach separates out the CO2 at the oil refinery and then burying it in the ground.
- Weather modification. One might calculate how much particulate matter might be needed for a global reduction in temperature.
- Algae Blooms. They thrive on iron and they absorb CO2.
- Rain Clouds. Using silver iodide crystals.
- Plant Trees.
- Calculating Virtual Weather.
The weather forecasting includes a lot of uncertainty. Quantum are much better than digital when it comes to uncertainty.
The sun in a bottle
How to bring sun energy down to earth. The leading candidate is called fusion.
There are actually two ways to unleash this nuclear fire. One can fuse hydrogen together to form helium via fusion, or one can split apart the uranium or plutonium atom to release nuclear energy via fusion.
The most popular design for the fusion reactor is called the tokamak, a Russian design.
The problem is that it is exceedingly difficult to create a powerful magnetic field to squeeze superhot hydrogen gas in the shape of doughnut long enough to create fusion.
The ITER is the most ambitious fusion project in the world.
Fusion is the solution to power society in the second half of this century.
Superconductors are important for this type of reactions.
Changing the parameters in a quantum computer program is dramatically cheaper than redesigning an entirely new billion-dollar fusion reactor magnet. Another application of quantum computers is to decipher how high-temperature ceramic superconductors work.
Simulating the universe
Science has been so successful that scientists are now drowning in an ocean of data, and quantum computers may be necessary to organize and analyze this deluge of information.
Looking beyond our solar system, there is another reason to use quantum computers, and this is to catalogue all the planets circling other stars. One goal that quantum computers will focus on is the search for other intelligent life-forms.
One day quantum computers will be able to explain the entire life history of stars, including the sun, and also potentially dangerous unstable stars in our vicinity.
Quantum computers excel as search engines, finding that elusive needle in the haystack.
So far, the leading (and only) candidate for a quantum theory beyond the Standard Model is string theory. It says that all elementary particles are nothing but musical notes on tiny vibrating strings. When calculating the nature of these vibrations, one can find gravity (that is missing in the Standard Model).
One day, it might be possible to put string theory onto a quantum computer to select out the correct path.
A day in the year 2050
Remember what happened at the end of The Hitchhiker’s Guide to the Galaxy? After much anticipation and excitement, a giant supercomputer finally calculates the meaning of the universe. But the answer turns out to be the number forty-two.
Quantum puzzles
A short list of questions that will stump most physicists?
- Did God have a choice in making the universe?
- Is the universe a simulation?
- Do quantum computers compute in parallel universes?
- Is the universe a quantum computer?
We want our universe to be stable. A Newtonian model of the atom is inherently unstable. The quantum theory solves this problem, because electron is described by a wave. The only way for quantum computers to create stable universes is to begin with the Schrodinger equation.
Everett’s many worlds theory is perhaps the simplest and most elegant way to resolve the measurement problem. Another theory is called decoherence theory, that states that interactions with the external environment cause the wave to collapse. In the Copenhagen approach, decoherence is introduced by the experimenter.
A quantum Turing machine can encode the laws of quantum mechanics, which in turn rule the universe.
Since all the interactions at the microscopic level are governed by quantum mechanics, it means that quantum computers can simulate any phenomenon of the physical world, from subatomic particles, DNA, and black holes to the Big Bang.
[1] In the book on page 41
