Feature/isometries

[emanuel-malvetti]

This branch implements decompositions for arbitrary isometries, diagonal gates and uniformly controlled single-qubit gates. (There is also code for uniformly controlled Rz rotations but it is not exposed in the interface.) Everything works well with controls, dagger and simulations except that isometries cannot be simulated. Everything is implemented both in C++ and Python.

A "master test" can be found in projectq/ops/_isometry_test.py

Relevant Papers:

Raban Iten, Roger Colbeck, Ivan Kukuljan, Jonathan Home, and Matthias Christandl. Quantum circuits for isometries. Phys. Rev. A, 93:032318, Mar 2016.

V. Bergholm M. Möttönen, J. J. Vartiainen and M. M. Salomaa. Quantum circuits with uniformly controlled one-qubit gates. Phys. Rev. A, 71:052330, 2005.

V. V. Shende, S. S. Bullock, and I. L. Markov. Synthesis of quantum-logic circuits. IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 25(6):1000–1010, 2006.

[Takishima]

Please fix the few issues I marked. Once that's done, I will go over this PR once again.

[CLAassistant]

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1 out of 2 committers have signed the CLA.

✅ Takishima
❌ Emanuel Malvetti

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