After about 55 years of Moore’s Law, named after Intel’s co-founder Gordon Moore, processors have reached their limit and the dominant architectural techniques have reached their limits in energy efficiency.
Fortunately, quantum computing comes at a time when Moore’s Law has run out, Dr. Ismail Akhalwaya, research scientist at IBM Research Lab in Africa, told TechRadar Middle East in an exclusive interview.
“Moore’s Law is about doubling the number of transistors on a microchip about every two years and this trend is now over. However, with quantum bits, it is a completely new type of computing regime and it is not just more of Moore’s Law,” he said.
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What is quantum bit or qubit?
On a classical computer, data can be processed in an exclusive binary state at any point in time, that is, either 0 (off) or 1 (on) but in quantum computing, it can work in two-way mode which means that it can be in a superposition of 0 and 1 via a qubit or quantum bit. Qubits can be in multiple basis states at the same time, which is known as quantum superposition.
So, while one qubit can be in a superposition of two states, 10 qubits, exploiting entanglement, can be in a superposition of 1,024 states. This phenomenon leads to an exponential growth of the possible states that can be represented concerning the number of qubits.
Doubling quantum volume
Akhalwaya said that IBM has been at the forefront of keeping Moore‘s Law as long as it can but the world needs increasing processing power.
“With our quantum computers, we have been doubling quantum volume every year for the last three years. The challenge is how to keep the noise [environmental influence] down. Every time we add one more qubit, we double the power, but we also possibly increase the noise,” he said.
Moving forward, Akhalwaya said there are two laws.
According to Google, the law is known as Neven’s Law, named after Hartmut Neven, director of Quantum Artificial Intelligence Lab, and it states that quantum computing power should grow at a double exponential rate compared to classical computing.
As per IBM, he said it’s known as Gambetta's Law, named after IBM Fellow Jay Gambetta, which states that “we seem to be on a path to doubling quantum volume every year and if we continue, we should reach quantum advantage in the 2020s.”
IBM has recently placed the largest quantum computer in the cloud, 53 qubits, and it is available to its more than 80 Q Network customers, including Wells Fargo, which joined this past week.
“We have been making steady progress and one of the strongest measures of success is what we call quantum volume. It is a good measure to show not only the increasing number of qubits but also that the quality of the qubits is increasing as well. We have been doubling the quantum volume,” he said.
With quantum volume, it is not only the qubits that matter, he said and added that it is also how noise creeps in with the qubits.
So, in a quantum computer, he said that noise creeps in and destroys the qubits.
“So, the quantum volume is the largest number of qubits by the longest time that you can run the programme before noise creeps in. We currently have a quantum volume of 16. But, quantum mechanics has a strange property.”
Trying to cut down the environmental influence
“Unlike in a classical computer, we have stable bits and they don’t get lost and the environment does not impact the bits. In the quantum case, the environment interferes with the delicate state and information leaks out, which means that environmental influence creeps in and washes out the information.
Window of opportunity
“As long as you have a good window of opportunity, you can extend the window by using error correction. We are working towards that. Commercial implementation of quantum computers is happening now, but it is still five to 10 years away for mass adoption. In the meantime, we are trying to find out new use cases and still work in the presence of noise,” Akhalwaya said.
For example, he said one client took seven years to incorporate GPU into their workplace and so, you can imagine how much time it will take to incorporate quantum computing.
Quantum computing has many benefits; he said and added that it has a massive speedup in many types of calculation, especially in the chemical world.
“We can get better chemical simulations to work out the energy level, reaction rates and design molecules, the impact should be similar to how materials science has already changed our world,” he said.
“When you do stimulation of chemical reaction or chemical energy levels, it is not that accurate on a classical computer or in a supercomputer. We don’t get the chemistry numbers right and that is because chemistry involves quantum mechanics,” he said.
The way electrons move around within the atoms and the joining of molecules is a quantum mechanical process and quantum mechanics involve multiple steps.
Extending window of computation
In a chemical reaction, Akhalwaya said that single additional electrons can double the number of possible configurations of a molecule. The doubling possibility of a chemical reaction cannot be kept up with a classical computer.
Akhalwaya said that “we will need millions of noisy qubits.”
To extend the window of computation, what“we can do is take the noisy qubits and use it to represent a clean qubit that can last indefinitely. We need 1,000 noisy qubits to build one clean qubit. So, to get 1,000s of clean qubits, we need millions of noisy qubits, but it is possible,” he said.
“We know from classical experience that in an old car, every single part may need to be replaced but you can still drive the car for some time. When a problem arises, you change only that part,” he said.
In the same way, with a quantum computer, “we can build qubits that can compute for longer periods from parts that last a few milliseconds and that is made possible by technology, mathematics and a proper understanding of the physics.”
There is no point in building a quantum computer with 1,000 noisy qubits, he said.
“You have to make them while keeping the noise down. These qubits are sitting on a silicon substrate and this substrate itself is interfering with the qubits and the qubits interfering with neighbouring “There is no point in just increasing the qubits until we steadily decrease the noise levels but we expect to double the quantum volume, the cleanliness of the qubits and the number of qubits in the same way Moore‘s Law doubled,” he said.
IBM has 14 quantum computers available for its customers.
Akhalwaya said the mission is to increase the quantum volume every year and involve more corporates and universities to get new use cases.
“We believe in a hybrid model of quantum and classical computing for the next few decades. We need classical computers to load the information on to quantum computers. It will be like a GPU on a classical computer. We use the GPU only when we need it. So, we will be using quantum computers only when we need it like a GPU. It does not mean that quantum computers will replace classical computers,” he said.