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Questions tagged [algorithms]

For questions about an algorithm as it relates to physics. DO NOT ask how to implement an algorithm, questions like that belong on Stack Overflow or Computational Science. DO NOT ask about the efficiency of an algorithm, or other such questions, questions like that belong on Computational Science.

7 votes
1 answer
2k views

Explanation of relaxation method for Laplace's equation?

Currently reading through Introduction to Electrodynamics (4th Edition) by Griffiths. I'm trying to wrap my head around Laplace's Equation, here are a couple quotes that I'd like to understand a bit ...
Bookie's user avatar
  • 237
9 votes
2 answers
2k views

Shor's algorithm - why doesn't the final collapse of the auxiliary qubits cripple the computation?

Let's look at quantum subroutine of Shor's algorithm (image source): Hadamard gates create superposition of all (exponential number) values for input qubits. Then we perform a classical function ...
Jarek Duda's user avatar
1 vote
2 answers
2k views

How to calculate the maximal Lyapunov exponent(s) of a multidimensional system?

I've been reading up about Lyapunov exponents for a university group project on chaos theory and I'm a little confused as to how they are calculated for a system of multiple dimensions. From what I ...
R.McGuigan's user avatar
29 votes
4 answers
840 views

Upper bounding the Kolmogorov Complexity of the Standard Model

The Kolmogorov complexity of a hypothesis/theory/model is the shortest computer program that simulates it, regardless of how inefficient executing that program may be in terms of memory and time. I'm ...
Craig Gidney's user avatar
  • 7,012
9 votes
2 answers
5k views

Numerical Ising Model - Wolff algorithm and correlations

I'm doing some numerical Monte Carlo analysis on the 2 dimensional Ising model at the critical point. I was using the Metropolis 'single flip' evolution at first with success, though it suffers from ...
Learning is a mess's user avatar
5 votes
2 answers
6k views

Quantum XOR: How do you generalize it?

Consider the classical XOR Gate: Given a 2 bit system: $G = [u_1, u_2]$ $$XOR(G) = (u_1 + u_2) \ mod \ 2$$ Is the following a good generalizaiton of a Quantum XOR Gate: Given a 2-qubit system: $...
Sidharth Ghoshal's user avatar
5 votes
1 answer
542 views

Deutsch's Algorithm. Unitary Transform $U_f$

I'm studying Deutsch's algorithm and I keep coming across the phrase along the lines of "There is a unitary transform (a sequence of quantum gates) $U_f$ that transforms the state $|x\rangle |y\rangle ...
Zach Dean's user avatar
2 votes
1 answer
426 views

Is estimation partition functions without resorting to markov chain monte carlo still an open question?

I was told estimation of partition functions without resorting to MCMC was still an open question in physics about a year and a half ago. An example is that say you have some physical model that ...
www3's user avatar
  • 73
2 votes
1 answer
342 views

Can I state that $\Psi (x_1, \dots , x_n,t)= \sum_{i=1}^n a_i \psi (x_i,t) $ via superposition?

Given that the hamiltonian $\hat H$ of a system is a linear operator and $\dot \psi (x_i,t)$ does not depend on spatial coordinates $x_1, ..., x_n$ with bases $\hat e_1, ... , \hat e_n$ can I state ...
bolzano's user avatar
  • 196
1 vote
0 answers
230 views

Shor's algorithm - its causality and similar exploitation of QM?

Shor's algorithm is rather the most interesting quantum algorithm as it shifts a problem which is believed to need exponential classical time, to polynomial time for quantum computer, additionally ...
Jarek Duda's user avatar
0 votes
2 answers
290 views

Shor's algorithm with adversary - can (delayed) erasure of value qubits cripple calculations?

Let's look at quantum subroutine of Shor's algorithm: Hadamard gates create superposition of all (exponential number) values for input qubits. Then we perform a classical function on them, which is ...
Jarek Duda's user avatar