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In classical binary computers, real numbers are often represented using the IEEE 754 standard. With quantum computers you can of course do this as well - and for measurements this (or a similar standard) will probably be necessary since the result of any measurement is binary. But could real numbers be modeled more easily and / or more precisely within the qubits using different methods before the measurement happens? If so, are there any use cases where this is actually useful, seeing that (I'm assuming) any additional precision will be lost when measurements are performed?

To be clear, I'm not (necessarily) looking for existing standards, just for ideas or suggestions on how to represent those numbers. If there's any research into it, that would be useful too of course.

Sanchayan Dutta
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blalasaadri
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2 Answers2

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There have been efforts to implement construct "floating point" representation of small rotations of qubit states, such as: Floating Point Representations in Quantum Circuit Synthesis. But there doesn't seem to be any international standard like the one you mentioned i.e. IEEE 754. IEEE 7130 - Standard for Quantum Computing Definitions is an ongoing project. Anyhow, representation of floating point will automatically be dependent on the precision you want. If you want to follow the path in the first paper I linked (i.e. using qubit rotations) I can already imagine the possibility of errors during such rotation operations and you'd have to deal with them accordingly.

Sanchayan Dutta
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I am afraid that while interesting work is being done here, it should be clear that the quantum computer architecture is very much non-standardised and hence this is all subject to change.

The IEEE 754 standard describes how to implement a feature that decades of engineering and research have shown to be useful and hence machines are to be expected to do this.

In contrast, scientists and engineers are still figuring out how to best create an 'universal' quantum computer. They have some ideas on how to do this, as Blue mentions. However, there is no 'one true idea' on which engineers can base standards.

Perhaps it would even turn out complex numbers are easier to represent on a quantum computer and we have a standard for complex number data-types, instead!

So, while work is being done here, an IEEE standard seems very much in the far future.

Discrete lizard
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