Lifeboat Foundation

In the general formulation of quantum information, quantum states are represented by a special class of matrices called density matrices. This lesson describes the basics of how density matrices work and explains how they relate to quantum state vectors. It also introduces the Bloch sphere, which provides a useful geometric representation of qubit states, and discusses different types of correlations that can be described using density matrices.

0:00 — Introduction.
1:46 — Overview.
2:55 — Motivation.
4:40 — Definition of density matrices.
9:55 — Examples.
12:58 — Interpretation.
15:37 — Connection to state vectors.
20:13 — Probabilistic selections.
25:23 — Completely mixed state.
28:41 — Probabilistic states.
32:03 — Spectral theorem.
37:36 — Bloch sphere (introduction)
38:36 — Qubit quantum state vectors.
41:30 — Pure states of a qubit.
43:52 — Bloch sphere.
47:38 — Bloch sphere examples.
51:36 — Bloch ball.
55:40 — Multiple systems.
56:46 — Independence and correlation.
1:00:55 — Reduced states for an e-bit.
1:04:16 — Reduced states in general.
1:08:53 — The partial trace.
1:12:23 — Conclusion.

Continue reading “Lesson 09: Density Matrices | Understanding Quantum Information & Computation” »

Brain-inspired spiking neural networks have shown their capability for effective learning, however current models may not consider realistic heterogeneities present in the brain. The authors propose a neuron model with temporal dendritic heterogeneity for improved neuromorphic computing applications.

New “metaholograms” could transform AR/VR technologies by enabling crosstalk-free, high-fidelity image projection with vastly increased information capacity.

Researchers have developed a new type of holograms, known as “metaholograms,” capable of projecting multiple high-fidelity images free of crosstalk. This innovation opens doors to advanced applications in virtual and augmented reality (AR/VR) displays, data storage, and image encryption.

Metaholograms offer several advantages over traditional holograms, including broader operational bandwidth, higher imaging resolution, wider viewing angle, and more compact size. However, a major challenge for metaholograms has been their limited information capacity which only allows them to project a few independent images. Existing methods typically can provide a small number of display channels and often suffer from inter-channel crosstalk during image projections.

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Aging is a natural part of life and yet one most of us hope to delay. At a certain point when you start feeling the effects of age and want the whole process to stop rushing forward. But can aging really be slowed down?

Continue reading “Can you delay aging? A biochemist explains how” »

Metal halide perovskites, a class of crystalline materials with remarkable optoelectronic properties, have proven to be promising candidates for the development of cost-effective thin-film transistors. Recent studies have successfully used these materials, particularly tin (Sn) halide perovskites, to fabricate p-type transistors with field-effect hole mobilities (μh) of over 70 cm2 V−1 s−1.

1I/2017 U1 (‘Oumuamua) was discovered in October 2017; shortly after, it was determined to be the first object ever seen inside the solar system that had come from beyond it. But by the time its origins had been discerned, the interstellar interloper had already rounded the Sun and was speeding away at some 85,700 mph (138,000 km/h). Just an estimated 1,300 feet (400 meters) across, it faded from view of even the most powerful telescopes within weeks.

The only way to gather more data and uncover its true nature would be to send a spacecraft to study it up close. But uncertainties in ‘Oumuamua’s exact trajectory, the difficulty of detecting its ever-dimming light, and its rapid retreat make the idea of designing, building, and launching a mission in time to catch up to it seem utterly impossible.

NVIDIA today announced that the world’s 28 million developers can now download NVIDIA NIM™ — inference microservices that provide models as optimized containers — to deploy on clouds, data centers or workstations, giving them the ability to easily build generative AI applications for copilots, chatbots and more, in minutes rather than weeks.

NVIDIA founder and CEO Jensen Huang will deliver a live keynote address ahead of COMPUTEX 2024 on June 2 at 7 p.m. in Taipei, Taiwan, outlining what’s next for the AI ecosystem. Tune in to watch it live. https://nvda.ws/3UXATRe

The space agency has been around since 1958, yet only a select few spacecraft have transported NASA astronauts to space. Boeing’s Starliner could join a rather exclusive list should it succeed in docking with the ISS and delivering its precious human cargo. We’ve put together a list of all the spacecraft that have flown, or will soon be flown, with NASA crews on board.