Skip to main content

Questions tagged [reversible-computation]

For questions related to reversible computing, i.e. computing models where each elementary operation (and hence every computation) can be undone.

Filter by
Sorted by
Tagged with
3 votes
2 answers
149 views

Does the Bell's state entanglement violate the reversibility property of unitary matrices?

I read unitary matrices are reversible, so when we apply a unitary operator $U$ on some input state and got an output state, then if we apply $U^\dagger$ (transpose conjugate) we get back the original ...
2 votes
1 answer
51 views

Do some Hamiltonian simulations require an irreversible process?

I just stumbled upon this research paper https://arxiv.org/abs/2309.16596. They claim to have found a problem which is easy to solve quantumly but hard classically: to find local minima of 2D ...
2 votes
2 answers
181 views

What role does Landauer's principle play in quantum reversibility?

In section 3.2.5 of Nielsen and Chuang (starting page 153) they talk about Landauer’s principle, where they discuss the lower bound on the thermodynamic cost of erasing information. In irreversible ...
3 votes
0 answers
195 views

Is it known that Clifford circuits are not universal for classical computation?

I'm interested in whether there is some known result about Clifford circuits being insufficent for classical computation. Aaronson and Gottesman in their 2004 paper Improved Simulation of Stabilizer ...
6 votes
1 answer
417 views

Thermodynamic Speed Limit to Quantum Computing

There's a lot of mystifying jargon in the field of quantum computation, so I would like to examine some elementary physics to maybe help clarify the assumptions being made. Is it not true that the ...
3 votes
1 answer
479 views

How does one convert a truth table to a square permutation matrix?

Given a classical circuit of $m$ inputs and $n$ outputs, composed of various AND gates, OR gates, NOT gates, etc., a truth table is a $2^{m}\times(m+n)$-sized matrix, where, in general, the first $m$ ...
2 votes
1 answer
289 views

"Bennett’s trick" for reversible circuits

A textbook approach, attributed to Charlie Bennett, for creating reversible circuit which outputs the input qubits and the initialized ancilla qubits involves copying the function output between the ...
4 votes
1 answer
188 views

How to build a quantum circuit of a given reversible function?

Given a function $f : \{0,1\}^n \longrightarrow \{0,1\}^m$ and a function $g : \{0,1\}^m \longrightarrow \{0,1\}^n$ that both can be computed by polynomial-size classical circuits such that $g(f(x))=x$...
7 votes
2 answers
986 views

How universal is the Toffoli gate for classical reversible computing?

It is easy to see that no finite set of classical reversible gates can be strictly universal (without ancilla) for classical reversible computation: for any reversible gate on $n$ bits, in its action ...
1 vote
2 answers
133 views

Can there be different gate implementations of same oracle implementation?

I have been reading about Bernstein-Vazirani Algorithm, and it uses what is known as a phase oracle. Basically, it is CNOT gate with several controls attached to the ancilla qubit $|-\rangle$ (it is ...
4 votes
0 answers
122 views

Universality for reversible classical computation

Is there any way to check whether a set of gates (for example, take the set comprising of the CNOT gate and the Hadamard gate) is universal for reversible classical computation? I can think of trial ...