Electronics has given us many types of computers. Starting from huge supercomputers, we have seen desktop computers, personal computers, handheld minicomputers, smartphones, palm-sized computers, and even chip-sized microcomputers. These computers commonly use electronic devices for functioning. According to PCB Trace Technologies Inc, there is another type of computer, and it does not use any type of electrical device to operate. Instead, it uses individual atoms as its operational medium and therefore, its name is quantum computer.
Being extremely powerful, quantum computers can easily solve all kinds of complex problems, starting from those related to cancer, street traffic regulation, weather forecasting, and many more, which regular computers struggle to do. Although quantum computers are still in active development, and have been for a couple of decades now, we have witnessed the first rudimentary versions recently.
How do Quantum Computers Work?
Quantum mechanics, the mechanism of particles down to the size of atoms, shows many strange properties that do not exist at higher or molecular levels. Quantum computers take advantage of these properties to provide solutions much faster than conventional computers can.
For instance, a drug can impact a cancer cell in many ways. In fact, there are so many factors involved that a regular computer takes a long time to sort through all of them. Similarly, calculating the best way to control streetlights to direct cars and reduce traffic can tie up a traditional computer for hours. For example, reducing or increasing the stoplight for 30 seconds may seem rudimentary for reducing the traffic on one road. However, this small change can increase the traffic on another road, as cars will have to wait that much longer to cross over. Such complex problems with several potential solutions can take a conventional computer a long time to find the optimal solution. However, a quantum computer works uniquely, sorting through all possible solutions and can provide answers within a matter of minutes.
Regular Computers Vs. Quantum Computers
Regular computers use billions of tiny electrical devices known as transistors. Computers use these transistors to map information into a binary language of 1’s and 0’s. Known as bits, these 1’s and 0’s are the building blocks of information, just like the letters of a spoken language are. A regular computer uses these building blocks of information to do various activities like loading apps, downloading files, streaming videos, and more. The computer creates a dictionary that can map any unit of data representing any number, letter, or symbol with a unique combination of bits. This way, the computer can work very powerfully.
Quantum computers also use the same language of 1’s and 0’s. However, rather than use transistors, they use elements from quantum mechanics. This is the field of physics that deals with the behavior of tiny objects like atoms or even smaller particles. The motion of such small particles is very different to our experience in daily life. Quantum computers harness this strange behavior and provide extremely fast solutions. Depending on the position of their electrons, atoms can have different energy levels. Quantum computers use the spin states of electrons to differentiate between 1 and 0 states.
Requirements of Quantum Computers
As quantum computers work with discrete states of atoms that can translate into quantum bits or qubits (0’s and 1’s), they are susceptible to noise, which can randomly change the state from 1 to 0 and vice versa, making the data useless. Atoms are incredibly tiny, and any movement or extra energy can affect them and change their state.
One of the ways that users of quantum computers reduce noise is by making the surrounding atmosphere cold—preferably as close as possible to absolute zero—the coldest that physics can reach. As heat is a form of energy, it can provide unwanted energy to the qubits and change their state erratically. Therefore, quantum computers need to operate at less than a fraction of a degree (500 milliKelvin) above absolute zero, or -270 °C (-460 °F).
Apart from heat, there are other types of energy that may also create noise. These are external electrical or magnetic fields, and vibrations from passing vehicles, or from accidental touch. Scientists developing quantum computers are always devising ways of reducing noise, which, for them, is a big ongoing problem. Typically, the quantum computer needs a lot of shielding, necessary not only to reach near-absolute zero temperatures, but also to limit other sources of noise reaching it.
The next requirement is to have a way of communicating with the qubits. As the computer uses quantum mechanics, the programs must also be unique, taking quantum properties into account.
Printed Circuit Boards for Quantum Computers
The major hurdle that printed circuit boards for quantum computers must face is their operating temperature of near absolute zero. At these cryogenic conditions, any electrical resistance generates heat, and this is detrimental to the operation of the quantum computer.
Therefore, rather than use copper, PCB manufacturers use aluminum, as aluminum behaves as a superconductor at 500 milliKelvin, the usual operating temperature for quantum computers.
Aluminum allows advanced wire-bonding at cryogenic temperatures. Aluminum also allows superconductivity near absolute zero temperatures, where all thermal activity shuts down. Both these properties allow producing low-tolerance circuits with aluminum, thereby opening up new ranges of applications.
Using aluminum, it is possible to have the entire electrical path as superconducting. This starts from aluminum wirebonding, to the copper/aluminum bilayer trace on the board, and ending at the solder pads. The superconducting behavior of aluminum results in increasing the performance and reliability of the quantum computer significantly.
As a result, it is possible to use circuits like COB or chip-on-board with zero electrical resistance and no heat generation. Moreover, the copper/aluminum bilayer also offers improved thermal conductivity, with the aluminum becoming a superconductor.
Although the quantum computer seems a great idea, engineers and physicists need many decades more of research and innovation to solve the many problems that beset them today. According to PCB Trace Technologies Inc, the quantum computer technology is at best in its early stages. Compare the recent release of IBM’s quantum computer with 20 qubits to the billions of bits your cellphone uses.