214 research outputs found
Analysis and minimization of bending losses in discrete quantum networks
We study theoretically the transfer of quantum information along bends in
two-dimensional discrete lattices. Our analysis shows that the fidelity of the
transfer decreases considerably, as a result of interactions in the
neighbourhood of the bend. It is also demonstrated that such losses can be
controlled efficiently by the inclusion of a defect. The present results are of
relevance to various physical implementations of quantum networks, where
geometric imperfections with finite spatial extent may arise as a result of
bending, residual stress, etc
Photonic simulation of entanglement growth and engineering after a spin chain quench
The time evolution of quantum many-body systems is one of the most important processes for benchmarking quantum simulators. The most curious feature of such dynamics is the growth of quantum entanglement to an amount proportional to the system size (volume law) even when interactions are local. This phenomenon has great ramifications for fundamental aspects, while its optimisation clearly has an impact on technology (e.g., for on-chip quantum networking). Here we use an integrated photonic chip with a circuit-based approach to simulate the dynamics of a spin chain and maximise the entanglement generation. The resulting entanglement is certified by constructing a second chip, which measures the entanglement between multiple distant pairs of simulated spins, as well as the block entanglement entropy. This is the first photonic simulation and optimisation of the extensive growth of entanglement in a spin chain, and opens up the use of photonic circuits for optimising quantum devices
Non-classical light state transfer in resonator networks
We use a normal mode approach to show full and partial state transfer in a
class of coupled resonator networks with underlying symmetry that
includes the so-called photonic lattice. Our approach defines an
auxiliary Hermitian coupling matrix describing the network that yields the
normal modes of the system and its time evolution in terms of orthogonal
polynomials. These results provide insight on the full quantum state
reconstruction time in a general network of any size and the full
quantum transfer time in the network of size with
In the latter, our approach shows that the Fock state
probability distribution of the initial state is conserved but the amplitudes
suffer a phase shift proportional to that results in partial quantum
state transfer for any other network size.Comment: 13 pages, 1 figur
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