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The Role of Semiconductors in Quantum Computing

Old Nassau_Princeton University_110821A
[Old Nassau, Princeton University - Office of Communication]


- Overview

Quantum computing is seen as the next logical step in producing faster, more efficient computers. Although it was theorized long ago, advances in nanotechnology and semiconductors in recent years have helped quantum computing move closer to mainstream use.

Normal computing operations use a bit (also known as a binary bit), which is the smallest unit of data in a computer and takes on a value of 0 or 1. Quantum computing uses a similar system of bits, called qubits. However, qubit values can be superimposed, so they can't actually take on two values, but one of three: 0, 1, and a 0 or 1 value. Thus, unlike conventional computers, this makes it possible to operate on two values at the same time.


- Principles for Building Quantum Computing Systems

Like bits in traditional computing, qubits are the building blocks, and all functionality stems from the qubit's behavior. Despite having three values, the math behind the function is complex, but in a nutshell, these individual qubits can have infinite values, which leads to a continuum of states. 

Quantum-mechanically storing information, a qubit is a two-state system that utilizes the 1/2 spin state of an electron (in the form of up or down), and through the polarization of a photon (which can be read as vertical or horizontal polarization). 

Qubits also undergo quantum entanglement, which means that qubits can become one and cannot be described independently, i.e. the results of operations are correlated, and the quantum state must be described as a whole system rather than a single qubit.  

Quantum computing relies on certain physical properties and directions of physics to provide the required computing power. It's not software, it's hardware technology, so the type of material used to build a quantum computer matters. For a quantum computer to operate efficiently, there are a few requirements that need to be met. 

The materials used generally need to have long-lived spin states, be able to control spin manipulation by external fields, be able to control the interaction between spins, be able to control the interaction between spins and external reservoirs, and be able to operate in Execute operations in parallel on multiple qubit systems. 

Furthermore, quantum systems must be almost completely isolated from their environment, coherent quantum states need to be preserved, decoherence times need to be long, and readout needs to be able to measure single spin states and bulk spin resonances of the electrons.



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