I recently read an interesting article in Science about how physicists have been able to store data in a Quantum Bit for 39 minutes at room temperature.
Before I go into details on why this is important or how it’s a step towards a new era of quantum supercomputers, it’s important to understand that Quantum Bits are the backbone of quantum computers.
In a quantum computer, information is stored as strings of 1 or 0. Imagine, multiple dots on a single line, and each dot can be in one state: either a “0” or a “1” at a single time. Qubit, short for quantum computation bit, is when that point isn’t limited by the state it can choose, meaning it can be a 0 and 1 at the same time. This property is called superposition.
Einstein’s theory of wave-particle duality says that a light particle can exist in two quantum states: either as a wave or a particle. Similarly, Qubits rely highly on this principle; one dot can exist either as 0 or as a 1.
Another way to understand quantum mechanics is to think about the famous thought experiment by Erwin Schrodinger where he puts a cat in a box along with a radioactive material and a hammer. At any time during the experiment the state of the cat, without opening the box, can be guessed as either live or dead. For the observer it can exist in both states: live and dead. That means without opening the box, the state of the cat is a superposition of two states. But, as soon as you open the box, the superposition is destroyed and the cat can be declared in one state: live or dead.
The two states of the same particle are connected and this is called quantum entanglement.
Now, because a Qubit doesn’t have to decide on a state, it can store data in either of its states and using this property, a Quantum computer will be able to do multiple calculations in parallel. The challenge is to manipulate several such Qubits at the same time while storing data in them. Qubits can store data for a long time in a superposition state but as soon as the state is destroyed by external human manipulation the data is lost.
D-wave systems has already developed a 512-qubit-quantum computer made from a superconductor whose quantum properties are brought into action when housed inside a cryogenics system at an absolute zero temperature. Physicists have recently shown that they were able to store data in a quantum bit for 39 minutes at room temperature.
You might have heard of the supercomputer Tianhe-2. It was recently named the “world’s fastest supercomputer”. Tianhe-2 can do 38 quadrillion calculations per second. Now a supercomputer is just a classical computer with a faster processor. The only reason why a quantum computer would be better than a supercomputer is because it can do similar calculations using lesser operations, so the result might be obtained a little faster.
So, how are these quantum computers useful? Well, they can be used to calculate the value of pi (π) or solve a system of linear equations, for starters. But, they can also be used to do more complex tasks like software validations and process optimization, or complex computational problems like peptide screening involved in drug discovery.
Last year Google, NASA and D-wave collaborated to make a new quantum computer. But, it will still be a few more years before we can throw away our computers and welcome a new generation of computers that hopefully will not freeze when you have multiple software programs running at the same time.