Two-qubit quantum gates construction via unitary factorization (pp0721-0746)
          Francisco Delgado
Quantum information and quantum computation are emerging research areas based on the properties of quantum resources, such as superposition and entanglement. In the quantum gate array version, the use of convenient and proper gates is essential. While these gates adopt theoretically convenient forms to reproduce computational algorithms, their design and feasibility depend on specific quantum systems and physical resources used in their setup. These gates should be based on systems driven by physical interactions ruled by a quantum Hamiltonian. Then, the gate design is restricted to the properties and the limitations imposed by the interactions and the physical elements involved. This work shows how anisotropic Heisenberg-Ising interactions, written in a non-local basis, allow  the reproduction of quantum computer operations based on unitary processes. We show that gates can be generated by a pulse sequence of driven magnetic fields. This fact states alternative techniques in quantum gate design for magnetic systems. A brief final discussion around associated fault tolerant extensions to the current work is included.

Universal asymmetric quantum cloning revisited (pp0747-0778)
          Anna-Lena Hashagen
This paper revisits the universal asymmetric $1 \to 2$ quantum cloning problem. We identify the symmetry properties of this optimization problem, giving us access to the optimal quantum cloning map. Furthermore, we use the bipolar theorem, a famous method from convex analysis, to completely characterize the set of achievable single quantum clone qualities using the fidelity as our figure of merit; from this it is easier to give the optimal cloning map and to quantify the quality tradeoff in universal asymmetric quantum cloning. Additionally, it allows us to analytically specify  the set of achievable single quantum clone qualities using a range of different figures of merit.

Efficient optimization of perturbative gadgets (pp0779-0793)
          Yudong Cao and Sabre Kais
Perturbative gadgets are general techniques for reducing many-body spin interactions to two-body ones using perturbation theory. This allows for potential realization of effective many-body interactions using more physically viable two-body ones. In parallel with prior work (arXiv:1311.2555 [quant-ph]), here we consider minimizing the physical resource required for implementing the gadgets initially proposed by Kempe, Kitaev and Regev (arXiv:quant-ph/0406180) and later generalized by Jordan and Farhi (arXiv:0802.1874v4). The main innovation of our result is a set of methods that efficiently compute tight upper bounds to errors in the perturbation theory. We show that in cases where the terms in the target Hamiltonian commute, the bounds produced by our algorithm are sharp for arbitrary order perturbation theory. We provide numerics which show orders of magnitudes improvement over gadget constructions based on trivial upper bounds for the error term in the perturbation series. We also discuss further improvement of our result by adopting the Schrieffer-Wolff formalism of perturbation theory and supplement our observation with numerical results.

Quantum walking in curved spacetime: (3+1) dimensions, and beyond (pp0794-0824)
          Pablo Arrighi and Stefno Facchini
A discrete-time Quantum Walk (QW) is essentially an operator driving the evolution of a single particle on the lattice, through local unitaries. Some QWs admit a continuum limit, leading to familiar PDEs (e.g. the Dirac equation). Recently it was discovered that prior grouping and encoding allows for more general continuum limit equations (e.g. the Dirac equation in $(1+1)$ curved spacetime). In this paper, we extend these results to arbitrary space dimension and internal degree of freedom. We recover an entire class of PDEs encompassing the massive Dirac equation in $(3+1)$ curved spacetime. This means that the metric field can be represented by a field of local unitaries over a lattice.

Pretty good state transfer between internal nodes of paths (pp0825-0830)
          Gabriel Coutinho, Krystal Guo, and Christopher M. van Bommel
In this paper, we show that, for any odd prime $p$ and positive integer $t$, the path on  $2^t p -1$ vertices admits pretty good state transfer between vertices  $a$ and $(n+1-a)$ for each $a$ that is a multiple of $2^{t-1}$ with respect to the quantum walk model determined by the XY-Hamiltonian. This gives the first examples of pretty good state transfer occurring between internal vertices on an unweighted path, when it does not occur on the extremal vertices.

Parallel self-testing of (tilted) EPR pairs via copies of (tilted) CHSH and the magic square game (pp0831-0865)
          Andrea Coladangelo
Device-independent self-testing allows a verifier to certify that potentially malicious parties hold on to a specific quantum state, based only on the observed correlations. Parallel self-testing has recently been explored, aiming to self-test many copies (i.e. a tensor product) of the target state concurrently. In this work, we show that $n$ EPR pairs can be self-tested in parallel through $n$ copies of the well known CHSH game. We generalise this result further to a parallel self-test of $n$ tilted EPR pairs with arbitrary angles, and finally we show how our results and calculations can also be applied to obtain a parallel self-test of $2n$ EPR pairs via $n$ copies of the Mermin-Peres magic square game.