06 November 2011

Quantum Computers: Tomorrows Technology

Quantum computers are the next step in the evolution of computers.

Quantum computers are being studied more by physicists than engineers. Why? Because these computers employ quantum mechanics. This has to do with the way quantum computers are built. But what makes them special?

Our present day computers use transistors to compute. The more transistors in a computer chip, the more processing power it has. The record for most number of transistors put on a chip is 2 billion. A quantum computer uses atoms for its computing power. To put simply, atoms, the way they behave, makes computing faster. To understand how this works, we have to look at how classical computers work.

We are in the digital age. In a way, digital means our information are stored in bits. Bits can store 2 kinds of information simply 0 or 1. Information and calculations are processed in a steady stream of bits of 0s and 1s.

A Quantum computer does not use bits to store information. It uses quantum bits or qubits. A qubit is basically an atom that carries the information just like a bit does. But unlike a bit, it just doesn't hold a 1 or 0 state. In an atom, it can have a spin-up stage (1) or a spin-down stage (0). But aside from that, an atom can be in both stages at the same time. This peculiar property of the atom is what everyone is excited about.

Video: Dr. Dominic Walliman explains Quantum Computers

In terms of computing power, this means that a quantum computer can theoretically perform a calculation in one step where a classical or digital computer may take several. A classical computer can be programmed to dial a million phone numbers, it will perform this by dialing a phone one million times. A quantum computer can dial the same million numbers all at the same time, in one step.

The possibilities of this are staggering. Quantum computers will revolutionize everything. A computer algorithm that may take years to decipher a coded message would take minutes if not seconds. Calculating the value of PI would be so fast that we won't be able to go thru each number in one lifetime. And sadly, even computer hackers would find it easy to infiltrate a system.

We are still way behind in creating that true quantum computer. We are still at an early stage of quantum technology. The ones we have now are still not practical but what we have now holds promise.

Physicists in University of Wisconsin-Madison studying the possibility of a quantum computer created a quantum computing circuit in 2010. This was a major step in quantum computing technology.

Recently, David Awschalom and colleagues at the University of California, Santa Barbara discovered that silicon carbide can be used for quantum information processing. Prior to this, diamonds were a source of atoms for qubits. This is because, these atoms have electron spin states that can be controlled coherently and manipulated as quantum bits using light. Silicon Carbide, as their study suggests also share this property with diamonds.

Video: Decoherence and Quantum computers

Diamond based qubits have a longer decoherence time that enables it to perform a logical operation. And also, the information can be read out using light which means photons can be utilized in processing the information, a stumbling block on how to pass info to and from the qubit.

It is important that these atoms are stable or "coherent". As atoms, they are sensitive to everything, be it vibration, temperature, or even cosmic rays from the sun. They can be agitated and easily lose its state (or information in this case) which is called "decoherence".

Video: Quantum Computers in much more detail:

Moore's Law states that computer processing power continues to double every 18 months. This means that by the year 2030 or earlier, we will find that the circuits on a microprocessor will approach the atomic scale and quantum computing will be the norm.

We may be seeing the last decade of the Digital Age and now ready to enter the early years of the Quantum Age.


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