Poincaré sphere by Ciro Santilli 40 Updated 2026-08-21
A more photon-specific version of the Bloch sphere.
In it, each of the six sides has a clear and simple to understand photon polarization state, either of:
The sphere clearly suggests for example that a rotational or diagonal polarizations are the combination of left/right with the correct phase. This is clearly explained at: Video "Quantum Mechanics 9b - Photon Spin and Schrodinger's Cat II by ViaScience (2013)".
Photomultiplier tube by Ciro Santilli 40 Updated 2025-07-16
Can be used to detect single photons.
It uses the photoelectric effect multiple times to produce a chain reaction. In particular, as mentioned at youtu.be/5V8VCFkAd0A?t=74 from Video 1. "Using a Photomultiplier to Detect single photons by Huygens Optics" this means that the device has a lowest sensitive light frequency, beyond which photons don't have enough energy to eject any electrons.
Video 1. . Source. 2024. Wow this dude is amazing as usual. Unfortunately he's not using a single photon source, just an LED.
Here is a vendor showcasing their device. They claim in that video that a single photon is produced and detected:
One of the sequencers made by Oxford Nanopore Technologies.
The device has had several updates since however, notably of the pore proteins which are present in the critical flow cell consumable.
Official documentation: nanoporetech.com/products/minion (archive)
Figure 5.
Oxford nanopore MinION flow cell package.
Source.
Figure 6.
Oxford nanopore MinION flow cell front.
Source.
Figure 7.
Oxford nanopore MinION flow cell back.
Source.
Figure 8.
Oxford nanopore MinION flow cell pipette loading.
Source.
Figure 9.
Oxford Nanopore MinION connected to a Mac via USB.
Source.
Video 1.
Oxford Nanopore MinION software channels pannel on Mac.
Source.
Night climbing by Ciro Santilli 40 Updated 2025-07-16
IonQ by Ciro Santilli 40 Updated 2025-07-16
Video 2. Source. Co-founder of IonQ. Cool dude. Starts with basic background we already know now. Mentions that there is some relationship between atomic clocks and trapped ion quantum computers, which is interesting. Then he goes into turbo mode, and you get lost unless you're an expert! Video 1. "Quantum Simulation and Computation with Trapped Ions by Christopher Monroe (2021)" is perhaps a better watch.
NQIT by Ciro Santilli 40 Updated 2025-07-16
Video 1.
Quantum Computing with Networked Ion traps by NQIT (2018)
Source. The video is a bit useless. But it does show the networked approach proposal a little bit. Universal Quantum's homepage particularly rejects that.
Universal Quantum by Ciro Santilli 40 Updated 2025-07-16
As of 2021, their location is a small business park in Haywards Heath, about 15 minutes north of Brighton[ref]
Funding rounds:
Co-founders:
Homepage says only needs cooling to 70 K. So it doesn't work with liquid nitrogen which is 77 K?
Homepage points to foundational paper: www.science.org/doi/10.1126/sciadv.1601540
Video 1.
Universal Quantum emerges out of stealth by University of Sussex (2020)
Source. Explains that a more "traditional" trapped ion quantum computer would user "pairs of lasers", which would require a lot of lasers. Their approach is to try and do it by applying voltages to a microchip instead.
Video 2.
Quantum Computing webinar with Sebastian Weidt by Green Lemon Company (2020)
Source. The sound quality is to bad to stop and listen to, but it presumaby shows the coding office in the background.
Video 3.
Fireside Chat with with Sebastian Weidt by Startup Grind Brighton (2022)
Source. Very basic target audience:
Google Quantum AI by Ciro Santilli 40 Updated 2025-07-16
Google's quantum hardware/software effort.
The "AI" part is just prerequisite buzzword of the AI boom era for any project and completely bullshit.
According to job postings such as: archive.ph/wip/Fdgsv their center is in Goleta, California, near Santa Barbara. Though Google tends to promote it more as Santa Barbara, see e.g. Daniel's t-shirt at Video "Building a quantum computer with superconducting qubits by Daniel Sank (2019)".
Video 1.
Control of transmon qubits using a cryogenic CMOS integrated circuit (QuantumCasts) by Google (2020)
Source. Fantastic video, good photos of the Google Quantum AI setup!
IBM Quantum Computing by Ciro Santilli 40 Updated 2025-07-16
The term "IBM Q" has been used in some promotional material as of 2020, e.g.: www.ibm.com/mysupport/s/topic/0TO50000000227pGAA/ibm-q-quantum-computing?language=en_US though the fuller form "IBM Quantum Computing" is somewhat more widely used.
Rigetti Computing by Ciro Santilli 40 Updated 2025-07-16
Video 1.
Forest: an Operating System for Quantum Computing by Guen Prawiroatmodjo (2017)
Source. The title of the talk is innapropriate, this is a very basic overview of the entire Rigetti Computing stack. Still some fine mentions. Her name is so long, TODO origin? She later moved to Microsoft Quantum: www.linkedin.com/in/gueneverep/.

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