scholarly journals Tantalum pentoxide nanophotonic circuits for integrated quantum technology

2020 ◽  
Vol 28 (8) ◽  
pp. 11921 ◽  
Author(s):  
Lukas Splitthoff ◽  
Martin A. Wolff ◽  
Thomas Grottke ◽  
Carsten Schuck
Keyword(s):  
Tantalum Pentoxide ◽  
Nanophotonic Circuits ◽  
Quantum Technology

Nanophotonic tantalum pentoxide devices for integrated quantum technology

2020 ◽  
Author(s):  
Martin A. Wolff ◽  
Lukas Splitthoff ◽  
Thomas Grottke ◽  
Simon Vogel ◽  
Carsten Schuck
Keyword(s):  
Tantalum Pentoxide ◽  
Quantum Technology

scholarly journals Superconducting nanowire single-photon detectors integrated with tantalum pentoxide waveguides

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Martin A. Wolff ◽  
Simon Vogel ◽  
Lukas Splitthoff ◽  
Carsten Schuck
Keyword(s):  
Integrated Circuits ◽  
Detection Efficiency ◽  
Single Photon ◽  
Photonic Integrated Circuits ◽  
Photon Counting ◽  
Tantalum Pentoxide ◽  
Photon Detectors ◽  
Single Photon Detectors ◽  
Quantum Technology ◽  
Superconducting Nanowire

Abstract Photonic integrated circuits hold great potential for realizing quantum technology. Efficient single-photon detectors are an essential constituent of any such quantum photonic implementation. In this regard waveguide-integrated superconducting nanowire single-photon detectors are an ideal match for achieving advanced photon counting capabilities in photonic integrated circuits. However, currently considered material systems do not readily satisfy the demands of next generation nanophotonic quantum technology platforms with integrated single-photon detectors, in terms of refractive-index contrast, band gap, optical nonlinearity, thermo-optic stability and fast single-photon counting with high signal-to-noise ratio. Here we show that such comprehensive functionality can be realized by integrating niobium titanium nitride superconducting nanowire single-photon detectors with tantalum pentoxide waveguides. We demonstrate state-of-the-art detector performance in this novel material system, including devices showing 75% on-chip detection efficiency at tens of dark counts per second, detector decay times below 1 ns and sub-30 ps timing accuracy for telecommunication wavelengths photons at 1550 nm. Notably, we realize saturation of the internal detection efficiency over a previously unattained bias current range for waveguide-integrated niobium titanium nitride superconducting nanowire single-photon detectors. Our work enables the full set of high-performance single-photon detection capabilities on the emerging tantalum pentoxide-on-insulator platform for future applications in integrated quantum photonics.

scholarly journals Quantum Reinforcement Learning with Quantum Photonics

Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 33
Author(s):  
Lucas Lamata
Keyword(s):  
Machine Learning ◽  
Reinforcement Learning ◽  
Quantum Computation ◽  
Exchange Information ◽  
Quantum Machine Learning ◽  
Quantum Technology ◽  
Quantum Photonics

Quantum machine learning has emerged as a promising paradigm that could accelerate machine learning calculations. Inside this field, quantum reinforcement learning aims at designing and building quantum agents that may exchange information with their environment and adapt to it, with the aim of achieving some goal. Different quantum platforms have been considered for quantum machine learning and specifically for quantum reinforcement learning. Here, we review the field of quantum reinforcement learning and its implementation with quantum photonics. This quantum technology may enhance quantum computation and communication, as well as machine learning, via the fruitful marriage between these previously unrelated fields.

scholarly journals Visualizing atomic structure and magnetism of 2D magnetic insulators via tunneling through graphene

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhizhan Qiu ◽  
Matthew Holwill ◽  
Thomas Olsen ◽  
Pin Lyu ◽  
Jing Li ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Deep Understanding ◽  
Magnetic Coupling ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Electronic And Magnetic Properties ◽  
Conducting Path ◽  
Magnetic Insulators ◽  
Quantum Technology

AbstractThe discovery of two-dimensional (2D) magnetism combined with van der Waals (vdW) heterostructure engineering offers unprecedented opportunities for creating artificial magnetic structures with non-trivial magnetic textures. Further progress hinges on deep understanding of electronic and magnetic properties of 2D magnets at the atomic scale. Although local electronic properties can be probed by scanning tunneling microscopy/spectroscopy (STM/STS), its application to investigate 2D magnetic insulators remains elusive due to absence of a conducting path and their extreme air sensitivity. Here we demonstrate that few-layer CrI3 (FL-CrI3) covered by graphene can be characterized electronically and magnetically via STM by exploiting the transparency of graphene to tunneling electrons. STS reveals electronic structures of FL-CrI3 including flat bands responsible for its magnetic state. AFM-to-FM transition of FL-CrI3 can be visualized through the magnetic field dependent moiré contrast in the dI/dV maps due to a change of the electronic hybridization between graphene and spin-polarised CrI3 bands with different interlayer magnetic coupling. Our findings provide a general route to probe atomic-scale electronic and magnetic properties of 2D magnetic insulators for future spintronics and quantum technology applications.

scholarly journals Decoherence dynamics estimation for superconducting gate-model quantum computers

2020 ◽  
Vol 19 (10) ◽  
Author(s):  
Laszlo Gyongyosi
Keyword(s):  
Gaussian Noise ◽  
Quantum Computer ◽  
Computer Architectures ◽  
Quantum Circuits ◽  
Optimal Placement ◽  
Quantum Computers ◽  
Intermediate Scale ◽  
Layout Generation ◽  
Quantum Technology ◽  
Physical Layout

Abstract Superconducting gate-model quantum computer architectures provide an implementable model for practical quantum computations in the NISQ (noisy intermediate scale quantum) technology era. Due to hardware restrictions and decoherence, generating the physical layout of the quantum circuits of a gate-model quantum computer is a challenge. Here, we define a method for layout generation with a decoherence dynamics estimation in superconducting gate-model quantum computers. We propose an algorithm for the optimal placement of the quantum computational blocks of gate-model quantum circuits. We study the effects of capacitance interference on the distribution of the Gaussian noise in the Josephson energy.

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