Quantum computing

Binary mathematics, which governs the process of silicon circuit gates opening or closing for electron flow and of information storage, is based on a series of 0s and 1s. The idea behind quantum computing is that we replace this silicon with a row of individual atoms. Atoms are kind of like little magnets. They can be either pointed up or down. Quantum mechanics, however, is strange, and one of it’s strange properties is that an atom can, in a sense be both spinning up and down. An electron can be in two states at the same time (until a final measurement is made).This is a bit trickier than the typical convention of digital information, where a 0 could be an up spin and a 1 could be a down spin. Calculations of digital information in the macroscopic world can be done by flipping these 0s over and making 1s and vice versa. The fact that, in quantum mechanics, you can be in two places at once, makes quantum computing a bit more of a challenge. This is why, instead of bits, as in computing, qubits are used in quantum computing. A qubit can describe both 0 and 1 simultaneously. Each qubit is a complex mixture of 0s and 1s and has the capacity to hold much more storage. In this way atoms can store much more information than ordinary bits, since it can have a percentage of probability of being spinning wither up or down. A quantum computer can outperform a standard computer on various tasks, such as code cracking, that is why the CIA is so fascinated in them. This is a major advantage of quantum over classical computing.

Quantum computers are fascinating, however, do they exist? The short answer is: yes. At Seth Lloyd’s MIT laboratory, is a machine that looks a lot like a conventional MRI machine. However, the machine is a bit smaller. The machine produces a magnetic field by means of two parallel magnetic coils. Some sample material is placed in this magnetic field and if their atoms (which are initially aligned) point up we have a 0 and if it points down we have a 1. 

The next question is: if quantum computers are possible, why do we not have them on the desks of every office worker in the United States? The problem with quantum computers is disturbances from the outside world. These disturbances will destroy the delicate calculations that these atoms are seeking to preform. When atoms no longer vibrate in this unison, this is known as quantum decoherence. A truck pulling into my driveway or a cosmic ray can disturb a quantum calculation. Quantum calculations are based on the delicate spinning of atoms. Decoherence is the biggest problem with creating quantum computers. Atoms can quickly decohere and cause problems for the calculations. 

Another problem comes from the Heisenberg uncertainty principle. Calculations in the quantum realm are uncertain. Thus, it may take many tries to get the right answer. This causes even the results of arithmetical operations to be fuzzy.

The most complex calculation done on a quantum computer thus far is “3 x 5 = 15”. This doesn’t seem like much, however, it was done on only several individual atoms. This involved about 20 qubits.