For questions about the relation of Quantum Computing and Classical Computing, such as their relative perfomance.
7
votes
3answers
189 views
Simplest algorithm for intuitively demonstrating quantum speed-up?
What's the simplest algorithm (like Deutsch's algorithm and Grover's Algorithm) for intuitively demonstrating quantum speed-up? And can this algorithm be explained intuitively?
Ideally this would be ...
6
votes
2answers
84 views
The process for transferring Qubits between locations
I understand that right now Qubits are physical entities in a Quantum Computer and I am playing around on the IBM Quantum Computer as well as the Q# language and dipping my toes into the Quantum world ...
11
votes
4answers
230 views
Are quantum computers just a variant on Analog computers of the 50's & 60's that many have never seen nor used?
In the recent Question "Is Quantum Computing just Pie in the Sky" there are many responses regarding the improvements in quantum capabilities, however all are focussed on the current 'digital' ...
14
votes
6answers
442 views
If quantum speed-up is due to the wave-like nature of quantum mechanics, why not just use regular waves?
The intuition I have for why quantum computing can perform better than classical computing is that the wavelike nature of wavefunctions allow you to interfere multiple states of information with a ...
6
votes
1answer
64 views
What classical public key cryptography protocols exist for which hacking is QMA complete or QMA hard?
Such a public key cryptosystem would be "quantum safe" in the sense that quantum computers cannot efficiently solve QMA hard problems.
112
votes
14answers
24k views
Is quantum computing just pie in the sky?
I have a computer science degree. I work in IT, and have done so for many years. In that period "classical" computers have advanced by leaps and bounds. I now have a terabyte disk drive in my bedroom ...
6
votes
3answers
119 views
Are we certain that quantum computers more efficient than classical computers can be built?
I mean are we certain that they will be able to provide us a huge improvements (in some tasks) compared to clasical computers?
6
votes
3answers
104 views
Will Moore's Law be no longer effective once quantum computers are created? [duplicate]
Moore's law states that computer power doubles in every 18 months (more formally: "the number of transistors in a dense integrated circuit doubles about every two years."). Statistics suggest that ...
14
votes
2answers
2k views
Is quantum cryptography safer than classical cryptography?
Quantum computing allows us to encrypt information in a different way compared to what we use today, but quantum computers are much more powerful than today's computers. So if we manage to build ...
27
votes
6answers
6k views
Why is it harder to build quantum computers than classical computers?
Is it because we don't know exactly how to create quantum computers (and how they must work), or do we know how to create it in theory, but don't have the tools to actually execute it in practice? Is ...
12
votes
2answers
152 views
Is it possible to “calculate” the absolute value of a permanent using Boson Sampling?
In boson sampling, if we start with 1 photon in each of the first $M$ modes of an interferometer, the probability of detecting 1 photon in each output mode is: $|\textrm{Perm}(A)|^2$, where the ...
21
votes
4answers
2k views
Does Moore's law apply to quantum computing?
Plain and simple. Does Moore's law apply to quantum computing, or is it similar but with the numbers adjusted (ex. triples every 2 years). Also, if Moore's law doesn't apply, why do qubits change it?
5
votes
3answers
96 views
Can the theory of quantum computation assist in the miniaturization of transistors?
In his inaugural lecture, Ronald de Wolf states
People are working with quantum objects, but trying to make them behave as classical as possible. (...) Instead of suppressing them to make systems ...
6
votes
0answers
80 views
Empirical Algorithmics for Near-Term Quantum Computing
In Empirical Algorithmics, researchers aim to understand the performance of algorithms through analyzing their empirical performance. This is quite common in machine learning and optimization. Right ...
6
votes
1answer
49 views
Assessing speed-up via Quantum-Stochastic correspondence
You can make a natural correspondence between a quantum state vector and a classical probability vector, and between a quantum unitary operator and a classical stochastic matrix. There is also a ...
14
votes
2answers
424 views
In a Quantum Turing Machine, how is the decision to move along the memory tape made?
Let, for a Quantum Turing machine (QTM), the state set be $Q$, and the alphabet of symbols be $\sum=\{0,1\}$, which appear at the tape head. Then, as per my understanding, at any given time while the ...
6
votes
1answer
85 views
How does the Curry-Howard correspondence apply to quantum programs?
In words of Wikipedia,
The Curry–Howard correspondence is the observation that two families of seemingly unrelated formalisms—namely, the proof systems on one hand, and the models of computation ...
2
votes
1answer
65 views
What impact would have introducing the quantum switch effect in classical computing?
This divulgation article by Prof. Brukner talks about the possibility of creating a situation where
"A causing B" and "B causing A" which we call a quantum switch. Such a setup is similar to some ...
6
votes
2answers
215 views
Can classical algorithms be improved by using quantum simulation as an intermediary step?
I'm wondering whether even if we cannot create a fast quantum computer, simulating quantum algorithms can be a reasonable method for classical algorithms.
In particular, I'd like to see any results ...
11
votes
1answer
55 views
Quantum memory assisting classical memory
Consider a classical computer, one making, say, a calculation involving a large amount of data. Would quantum memory allow it to store that information (in the short term) more efficiently, or better ...
13
votes
3answers
375 views
Is the common Computer Science usage of 'ignoring constants' useful when comparing classical computing with quantum computing?
Daniel Sank mentioned in a comment, responding to (my) opinion that the constant speed-up of $10^8$ on a problem admitting a polynomial time algorithm is meager, that
Complexity theory is way too ...
33
votes
2answers
1k views
Is there proof that the D-wave (one) is a quantum computer and is effective?
I'm admittedly a novice in this field, but I have read that, while the D-wave (one) is an interesting device, there is some skepticism regarding it being 1) useful and 2) actually a 'quantum computer'....
0
votes
1answer
148 views
How much memory is required to simulate a 48-qubit circuit?
This CDMTCS Report 514, 2017 entitled "The Road to Quantum Computational Supremacy" states (in Section 6) that the amount of memory needed to simulate random quantum circuits on classical computers ...
