28 research outputs found
Experimental Perfect Quantum State Transfer
The transfer of data is a fundamental task in information systems.
Microprocessors contain dedicated data buses that transmit bits across
different locations and implement sophisticated routing protocols. Transferring
quantum information with high fidelity is a challenging task, due to the
intrinsic fragility of quantum states. We report on the implementation of the
perfect state transfer protocol applied to a photonic qubit entangled with
another qubit at a different location. On a single device we perform three
routing procedures on entangled states with an average fidelity of 97.1%. Our
protocol extends the regular perfect state transfer by maintaining quantum
information encoded in the polarisation state of the photonic qubit. Our
results demonstrate the key principle of perfect state transfer, opening a
route toward data transfer for quantum computing systems
Towards integrated superconducting detectors on lithium niobate waveguides
Superconducting detectors are now well-established tools for low-light
optics, and in particular quantum optics, boasting high-efficiency, fast
response and low noise. Similarly, lithium niobate is an important platform for
integrated optics given its high second-order nonlinearity, used for high-speed
electro-optic modulation and polarization conversion, as well as frequency
conversion and sources of quantum light. Combining these technologies addresses
the requirements for a single platform capable of generating, manipulating and
measuring quantum light in many degrees of freedom, in a compact and
potentially scalable manner. We will report on progress integrating tungsten
transition-edge sensors (TESs) and amorphous tungsten silicide superconducting
nanowire single-photon detectors (SNSPDs) on titanium in-diffused lithium
niobate waveguides. The travelling-wave design couples the evanescent field
from the waveguides into the superconducting absorber. We will report on
simulations and measurements of the absorption, which we can characterize at
room temperature prior to cooling down the devices. Independently, we show how
the detectors respond to flood illumination, normally incident on the devices,
demonstrating their functionality.Comment: 7 pages, 4 figure