Questions tagged [nisq]

For questions related to Noisy Intermediate Scale Quantum (NISQ) computing. NISQ computers cannot be classically simulated in a reasonable time but are not advanced enough to also be error corrected.

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23 views

Why is the VQE insensitive to noise?

I was going through the Grove documentation on the Variational Quantum Eigensolver. In one of the demonstrations with noisy gates, it is seen that resulting eigenvalue is quite close to the expected ...
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0answers
31 views

What is the implication of locality in QAOA?

Suppose I am solving the TSP formulated as a QUBO problem using QAOA. I understand from the original paper that there is a parameter $p$ which sets the number of steps used in thealternating ansatz. ...
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1answer
49 views

How is back-propagation done in “Transfer learning in hybrid classical-quantum neural networks”

Just read this paper from Xanadu on Quantum Transfer Learning and a couple of things are unclear to me regarding the optimisation step. How is back-propagation done through the classical weights ...
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1answer
109 views

What's the point of VQE if classical computers can solve for eigenvalues easily?

From a few VQE tutorials online I see that they normally start with something like: VQE is a way of getting a good estimate for the upper bound of the ground state of a quantum system's Hamiltonian....
2
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1answer
51 views

Will NISQ based algorithms be useful in fault-tolerant Quantum computers?

As a data scientist, I want to use the cutting edge algorithms of machine learning to build my models, I am interested in quantum machine learning, the recent research in QML is about variational ...
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0answers
26 views

Dealing with noise in NISQ

I wanted to know if there are some way in NISQ (we run "bare" gate without Q.E.C) to certify if an algorithm will give a correct or wrong answer based on the process of a single gate ? For example in ...
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0answers
116 views

What are the “nice” properties of the diamond norm and why is it used?

I have heard about the diamond norm, and from what I understood it is a "nice" tool to quantify quality of quantum gates in the NISQ era. I would like to know a little more before going in detail in ...
5
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3answers
614 views

Pennylane and Qiskit for quantum machine learning

I'm interested in quantum computing, specifically in “quantum machine learning” (QML). I'm going to start my masters program in computer science and have previous experience in classical machine ...
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0answers
60 views

Active areas of research for NISQ algorithms

What areas of research in NISQ algorithms have heavy focus? I'm interested in quantum chemistry algorithms because of previous work (e.g. VQEs), and I'd love to learn more about other near-term ...
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2answers
121 views

Software for Quantum Computing

From what I read classical computing evolved so quickly because of the funding-applications cycle. Even though the cost to make denser IC's was increasing rapidly, the applications were also getting ...
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1answer
132 views

Most efficient way for general state generation

Assume we are given an $n$-qubit system and complex numbers $a_0, \ldots, a_{m-1}$ with $m = 2^n$. Assume further we start with the initial state $|0 \ldots 0\rangle$ and want to make the ...
5
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1answer
116 views

Where does the Xmon simulator from Googles cirq framework its entropy from?

Measurements create entropy as we all know. But computers themselves are deterministic machines. Most devices use processor heat as a source for random number generation as far as I know - which has ...
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1answer
140 views

Minimum number of CNOTs for a 4-qubit increment on a planar grid

Recently I've been wondering how high NISQ machines will be able to "count". What I mean by that is, given the most optimized increment circuit you can make, how many times can you physically apply ...
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4answers
532 views

What use has quantum computing been?

Most of us on this site believe that quantum computing will work. However, let's play devil's advocate. Imagine that we suddenly hit some fundamental stumbling block that prevented further development ...
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1answer
213 views

Devising “structured initial guesses” for random parametrized quantum circuits to avoid getting stuck in a flat plateau

The recent McClean et al. paper Barren plateaus in quantum neural network training landscapes shows that for a wide class of reasonable parameterized quantum circuits, the probability that the ...
39
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1answer
9k views

What is meant by “Noisy Intermediate-Scale Quantum” (NISQ) technology?

Preskill introduced recently this term, see for example Quantum Computing in the NISQ era and beyond (arXiv). I think the term (and the concept behind it) is of sufficient importance that it deserves ...
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4answers
805 views

How should different quantum computing devices be compared?

In the last years, there has been a spur of demonstrations of devices able to perform proof of principle, small-scale, non-fault-tolerant quantum computation (or Noisy Intermediate-Scale Quantum ...