You may have seen some incredulous headlines in the news over the last few weeks, news that seems to take a page straight out of a science fiction novel:
- Scientists have reversed time in a quantum computer — Newsweek
- Scientists Used IBM’s Quantum Computer to Reverse Time, Possibly Breaking a Law of Physics — Discover Magazine
- Scientists ‘Reverse Time’ With Quantum Computer in Breakthrough Study — The Independent
No fundamental laws of physics were harmed in this experiment
In fact, all of these articles stem from the same Scientific Research journal article published in late February. The actual discovery, despite being momentous, is not nearly as sensational as these articles would have you believe.
The scientists from the U.S. and Russia essentially sent a basic unit of quantum information, called a qubit, from a complicated state to a simpler one. For those of you who remember learning about the second law of thermodynamics — namely that entropy in a closed system always increases — this experiment seems to potentially violate that fundamental law.
However, the solution wasn’t actually attained through a process so groundbreaking. Instead — an analogy — imagine an assembled jigsaw puzzle that is thrown from the table to the floor in a mass of jumbled, randomized pieces. The experiment is equivalent to throwing the disarray of pieces from the floor back to the table and having the pieces somehow magically assemble to form the initial image.
Theoretically, if you try this enough times (where “enough” here is an unfathomably large number), the pieces will eventually fall into place. Furthermore, if you control the parameters more — such as throwing them one by one, or by having a system compute exactly how to throw them, you’ll get the recombined picture in a significantly fewer number of tries.
By conducting this experiment inside a quantum computer, scientists were able to exert a level of control over the system that wouldn’t be possible under normal computing. And yes, that means unfortunately the short, small, and rigidly controlled experiment didn’t actually break any laws of physics.
What’s a quantum computer?
To understand quantum computing, let’s first look at a regular modern computer.
At the very basic level, modern computers are made up of billions of transistors, binary bits of 0’s and 1’s, which conduct electric current. Information is passed using electric pulses across these transistors. In “0” state, transistors are switched off and do not conduct any electric current. In “1” state, transistors are switched on and do conduct electric current.
Because these states are discrete and different, modern processors process one task or calculation at a time — there is no ‘half-task’ that can be done, and the state of these switches cannot be adjusted midway through the calculation. After a task is completed, the states have to be reset for the second task.
The quantum computer, on the other hand, uses qubits — tiny subatomic particles the size of electrons which follow the laws of quantum physics. Qubits can exist in multiple states between “0” and “1” simultaneously and can compute solutions for each and every intermediate state at the same time.
All the qubits in a system are entangled, i.e., dependent on each other. This means that if you measure the outcome of one qubit in an entangled system of two qubits, you can immediately deduce the outcome of the other qubit. Because each qubit exists in multiple states (unlike the on-off transistors in modern computers), quantum computers exhibit parallelism. Each qubit is a part of multiple calculations, all being executed in parallel — which helps it process hundreds of simultaneous computations.
Still confused? Maybe this video helps: see the video
Significance and possible applications of quantum computing
So, if not time travel, what did the initial Scientific Research article actually show us? Quantum computing can help scientists simulate processes that are nearly impossible to replicate using current computing standards. It has the potential to replace the modern transistor-based computers in a variety of industries, particularly where processing requirements are immense and using current computing devices makes getting results inefficient, expensive, and time-consuming.
Quantum computing can speed up the modeling of new drugs by more accurately simulating the interaction of these drugs with the human body. They can also increase trial success rates by using protein simulations to find binding sites for new drugs. Because of these reasons, the market potential for quantum computing in the pharma industry is estimated to be $15B — $30B in the next 10 years.
Quantum computers can simulate the modeling of chemical bonds and reactions, solving a variety of chemistry problems that exist today. Currently, even the most powerful supercomputers are insufficient to model anything but the most basic chemistry. By simulating these reactions better on a quantum computer, scientists expect to unlock low energy pathways for chemical reaction, allowing the creation of new chemical catalysts. This will have a huge impact on multiple applied chemical industries, such as fertilizer production or personalized medicine.
Machine Learning (ML)
Quantum AI can increase the effectiveness of ML by applying its characteristic parallelism to execute large queries and sift through mammoth databases. This exponential processing power can be applied to solve problems as wide ranging as the extraction of genetic data or modeling how carbon emissions affect climate change.
Quantum computing can be used to better model financial markets, because it’s able to include more variables and larger datasets without compromising on processing time. Applications of quantum computing in finance could include predicting optimum trading trajectories and credit scoring.
We are just starting to see the media hype regarding quantum computing and its potential impact. Will this or won’t this be the next 5G, AI, or blockchain? Hard to say.
First of all, quantum computing is also still very much at its infancy. There are significant challenges that need to be overcome in order to move the technology from the theoretical to the actual. And there’s also the general inaccessibility of the field — outside of physicists, the mechanisms of quantum physics are difficult for most people to understand, understandably.
Challenges (and impressive headlines) aside, one should keep an eye on quantum computing as a potential game-changer in the future. While we’re just starting to see large R&D-focused companies like IBM and Google begin to develop commercial computing systems that run on qubits, there’s a long road ahead for this exciting new technology.