Questions tagged [quantum-information]

Theoretical issues related to the quantum treatment of information

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26 votes
5 answers

Is there any connection between the diamond norm and the distance of the associated states?

In quantum information theory, the distance between two quantum channels is often measured using the diamond norm. There are also a number of ways to measure distance between two quantum states, such ...
Joe Fitzsimons's user avatar
21 votes
7 answers

Universities for Quantum Computing / Information?

Which universities have a strong quantum computing curriculum, and offer some type of quantum computing/information courses/research? The aim here is to collect a useful list for someone considering ...
Vincent Russo's user avatar
18 votes
1 answer

Polynomial speedups with algorithms based on semidefinite programming

This is a followup of a recent question asked by A. Pal: Solving semidefinite programs in polynomial time. I am still puzzling over the actual running time of algorithms that compute the solution of ...
Alessandro Cosentino's user avatar
11 votes
1 answer

Fast classical simulation of quantum algorithms

Are there examples of cases where the classical simulation of a quantum algorithm for a problem outperforms the best previously known classical algorithm for this problem? "Outperforms" doesn't have ...
delete000's user avatar
  • 818
9 votes
2 answers

Is adiabatic quantum computing as powerful as the circuit model?

Much of the quantum computing literature focuses on the circuit model. Adiabatic quantum computing is not based on applying a sequence of unitary operators, but on changing a time-dependent ...
vzn's user avatar
  • 11k
8 votes
1 answer

Quantum Money where not even the Bank can counterfeit

The Quantum Money system proposed in "Quantum Copy-Protection and Quantum Money" has the following properties: The bank can produce bank notes in the form of quantum states. Anyone can verify that ...
Christopher King's user avatar
5 votes
0 answers

Do the quantum communication complexity lower bounds hold when parties can send a "duplicated" qubits?

This question continues from the previous question where I mistakenly asked a question that is too general. In quantum communication complexity, we always assume that Alice and Bob have unlimited ...
Danu's user avatar
  • 763
3 votes
1 answer

How well can an arbitrary (unknown) quantum state be imperfectly cloned?

How well can an arbitrary unknown (quantum) state $\rvert \psi \rangle = \alpha\rvert 0 \rangle + \beta \rvert 1 \rangle$, be imperfectly/approximately cloned? Given an unknown state ${\rvert \psi \...
Subhayan's user avatar
  • 831
3 votes
1 answer

Questions about Farhi's pre-Adiabatic paper

I have been going through Eddie Farhi's 6-pages long pre-Adiabatic paper, An Analog Analogue of a Digital Quantum Computation. I guess I understand most of the math and physics but I am struggling ...
Omar Shehab's user avatar
1 vote
2 answers

Are Alice and Bob allowed to copy qubits in quantum communication complexity model?

In quantum communication complexity, we always assume that Alice and Bob have unlimited computational power and are still prove lower bounds such as the $\Omega(n)$ lower bounds of parity. What ...
Danu's user avatar
  • 763