Omar Shehab

99 reputation

bio	website	umbc.edu/~shehab1
	location	Baltimore
	age	29
visits	member for	6 months
	seen	May 17 at 2:38
stats	profile views	76

A PhD student studying quantum computation.

	99 reputation	bio	website	umbc.edu/~shehab1	visits	member for	6 months
11 badges		location	Baltimore		seen	May 17 at 2:38

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May 16	comment	NP-completeness of non-planar Ising model versus polynomial time eigenvalue algorithms This paper (DOI: 10.5488/CMP.15.43002) describes a hybrid system of both Ising and Heisenberg spins. In Equation 1, $\sigma_z$ is used for Ising spin and $S_z$ is used for Heisenberg spin.
May 16	comment	NP-completeness of non-planar Ising model versus polynomial time eigenvalue algorithms @Siva, it should be $d \ge 3$.
May 16	comment	NP-completeness of non-planar Ising model versus polynomial time eigenvalue algorithms @Lagerbaer, I think I know what went wrong with my understanding. I was trained as a computer scientist and doing my PhD in quantum computation. I learnt about Ising models from papers on adiabatic quantum computation (not by studying condensed matter physics). Papers like this (www-users.math.umd.edu/~mohara/mainthesis.pdf.gz), obviously not wrong but too simplified for me, generally express the Ising Hamiltonians in terms of Pauli spin matrices. So, I was brain washed with a limited understanding.
May 16	accepted	NP-completeness of non-planar Ising model versus polynomial time eigenvalue algorithms
May 16	comment	NP-completeness of non-planar Ising model versus polynomial time eigenvalue algorithms @Lagerbaer, as $S_i$ and $S_j$ are Pauli matrices, shouldn't be H always in matrix form? If so, for any Ising Hamiltonian, finding the ground state is always the problem of finding the eigenvalues, right? Say, for some reasons, which I don't understand, H is not always in matrix form. Can we then say that the ground states of at least those Ising models, which have Hamiltonians in matrix form, can be calculated in polynomial time? BTW, what are those Ising models which don't have a Hamiltonian in matrix form?
May 16	comment	NP-completeness of non-planar Ising model versus polynomial time eigenvalue algorithms @Lagerbaer, Now I am even more confused. What is exactly NP-complete here?
May 16	comment	NP-completeness of non-planar Ising model versus polynomial time eigenvalue algorithms @Lagerbaer, the Hilbert space is relevant when we try to write the Hamiltonian. So, should I assume that writing the Hamiltonian matrix, not solving it, is NP-complete?
May 16	asked	NP-completeness of non-planar Ising model versus polynomial time eigenvalue algorithms
May 9	awarded	Tumbleweed
May 6	revised	State emitting from an extended thermal source added 241 characters in body
May 6	asked	State emitting from an extended thermal source
May 2	asked	Physical significance of effective wave function
Apr 4	revised	First order coherence through double slit added 1065 characters in body
Apr 4	revised	First order coherence through double slit added 1065 characters in body
Apr 2	comment	First order coherence through double slit It's not complete. Can we consider the exponential terms to be unity?
Apr 2	answered	First order coherence through double slit
Apr 2	asked	First order coherence through double slit
Mar 26	accepted	Information bearing degrees of freedom of a quantum simple harmonic oscillator
Mar 26	asked	Information bearing degrees of freedom of a quantum simple harmonic oscillator
Mar 26	comment	How is the energy/eigenvalue gap plot drawn for adiabatic quantum computation? Yes, I was able to draw the plot.