
Whereas a standard transistor can perform only one operation at a time, a qubit can perform many simultaneously. Therefore a quantum computer containing the same number of transistors as an ordinary computer of today can be a million times faster. A 30-qubit quantum computer could perform as many as 10 teraflops - 10 trillion floating-point operations per second! Today's desktop computers perform gigaflops - billions of operations per second.

One problem with quantum computing is that if you observe the quantum state of a qubit, it changes. So scientists must devise an indirect method of determining the state of a qubit. To do this, they are trying to take advantage of another quantum property called "entanglement." At the quantum level, if you apply a force to two particles they become "entangled;" a change in the state of one particle is instantly reflected in the other particle's change to the opposite state. So by observing the state of the second particle, physicists hope to determine the state of the first.