OpenFermion Cirq Versions Save

Notable changes and additions:

• An implementation of the fermionic Fast Fourier Transform: openfermioncirq.ffft.
• Improved Givens rotation network for effecting one-body basis rotations: openfermioncirq.primitives.optimal_givens_decomposition.
• openfermioncirq.CubicFermionicSimulationGate.
• openfermioncirq.QuarticFermionicSimulationGate.

Deprecations:

• openfermioncirq.XXYYPowGate. Use cirq.ISwapPowGate with negated exponent, instead.
• openfermioncirq.XXYY. Use cirq.ISWAP with negated exponent, instead.
• openfermioncirq.YXXYPowGate. Use cirq.PhasedISwapPowGate, instead.
• openfermioncirq.YXXY. Use cirq.PhasedISwapPowGate, instead.
• openfermioncirq.CXXYYPowGate. Use cirq.ControlledGate and cirq.ISwapPowGate with negated exponent, instead.
• openfermioncirq.CXXYY. Use cirq.ControlledGate and cirq.ISWAP with negated exponent, instead.
• openfermioncirq.CYXXYPowGate. Use cirq.ControlledGate and cirq.PhasedISwapPowGate, instead.
• openfermioncirq.CYXXY. Use cirq.ControlledGate and cirq.PhasedISwapPowGate, instead.

Notable changes and additions:

• CombinedDoubleExcitationGate
• bogoliubov_transform and prepare_gaussian_state automatically detect spin symmetry and return optimized circuits if it is present
• Implemented FSWAP as an EigenGate, so it can be raised to a power
• Standardized common gate classes to take an exponent argument and have a name of the form NamePowGate. For example, XXYYGate is now XXYYPowGate and no longer takes rads, degs, or half_turns.
• Faster simulation of most gates on Cirq's simulator via defining the _apply_unitary_to_tensor_ magic method
• rot11, rotzz, Rxxyy, Ryxxy

Includes major changes to functionality for studying variational algorithms and the low rank Trotter step.

• Changed the protocol for defining a variational ansatz
• The objective function for variational algorithms is now represented by the VariationalObjective class
• VariationalStudy can track additional information, such as time spent, about optimization runs
• Utilize improved low rank decomposition from OpenFermion for low rank Trotter step
• Changed how the one-body terms are simulated in the low rank Trotter step
• Added a variational ansatz based on the low rank Trotter step

Minor package polish.

• Now requiring python 3.5.3+ instead of 3.5+ (https://github.com/quantumlib/Cirq/issues/710).
• Fixed error in variational algorithm tutorial.
• Put user installation instructions before dev instructions.
• Various doc fixes.

The first public alpha release of OpenFermion-Cirq! Launch features include:

• Linear depth linear connectivity Bogoliubov transformations.
• Framework for linear depth linear connectivity swap networks.
• Framework for implementing different types of Trotter steps
• Linear swap network DiagonalCoulombHamiltonian Trotter steps.
• Linear split operator DiagonalCoulombHamiltonian Trotter steps.
• Prototype functionality for arbitrary "low rank" Trotter steps.
• Framework for instantiating variational ansatz circuits.
• Framework for implementing variational algorithm studies.
• Variational ansatz circuits based on linear Trotter steps.
• Tutorial about basis transformations and free fermion models.
• Tutorial about Trotter steps of DiagonalCoulombHamiltonians.
• Tutorial about Trotter steps based on low rank decompositions.
• Tutorial about implementing variational algorithms, applied to jellium, H2.