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May 14, 2024

Quantum time dilation in a gravitational field

Posted by in categories: particle physics, quantum physics

Jerzy Paczos, Kacper Dębski, Piotr T. Grochowski, Alexander R. H. Smith, and Andrzej Dragan, Quantum 8, 1338 (2024). According to relativity, the reading of an ideal clock is interpreted as the elapsed proper time along its classical trajectory through spacetime. In contrast, quantum theory allows the association of many simultaneous trajectories with a single quantum clock, each weighted appropriately. Here, we investigate how the superposition principle affects the gravitational time dilation observed by a simple clock – a decaying two-level atom. Placing such an atom in a superposition of positions enables us to analyze a quantum contribution to a classical time dilation manifest in spontaneous emission. In particular, we show that the emission rate of an atom prepared in a coherent superposition of separated wave packets in a gravitational field is different from the emission rate of an atom in a classical mixture of these packets, which gives rise to a quantum gravitational time dilation effect. We demonstrate that this nonclassical effect also manifests in a fractional frequency shift of the internal energy of the atom that is within the resolution of current atomic clocks. In addition, we show the effect of spatial coherence on the atom’s emission spectrum.

May 14, 2024

China unveils 100kg liquid-hydrogen fuel system that could allow a truck to travel 1,300km without refuelling

Posted by in categories: energy, transportation

State-owned China Aerospace and Technology Corporation says the new technology meets international standards.

May 14, 2024

Cheap, Stylish New Kia EV3 Electric SUV Is Coming in May

Posted by in categories: sustainability, transportation

Tesla’s $25,000 EV is clouded with doubt, but Kia’s presumably inexpensive EV3 crossover is barreling ahead.

May 14, 2024

MediaTek And NVIDIA Reportedly Co-Developing Snapdragon X Elite Competitor, Design To Be Finalized In Q3, Using TSMC’s 3nm Process

Posted by in categories: economics, robotics/AI, space

Qualcomm’s Snapdragon X Elite will eventually face competition in the ARM-based AI chipset space from MediaTek and NVIDIA, who have reportedly joined forces to co-develop a new SoC whose design is said to be finalized in the third quarter of this year. The upcoming silicon is said to support advanced technologies, including being mass produced on TSMC’s 3nm process, with the new entrant possibly competing with Apple’s M4 when comparing lithography.

The unnamed chipset from MediaTek and NVIDIA is rumored to fetch a price of $300 per unit, likely due to leveraging advanced nodes and packaging technologies

With the AI PC segment estimated to grow massively by 2027, MediaTek and NVIDIA want to pounce on this opportunity, giving this category a healthy dose of competition. The Taiwanese fabless semiconductor manufacturer has already received praise from Morgan Stanley analysts for its Dimensity 9,300, so there is no question that the company’s chip-making prowess has a gold-standard label. Add NVIDIA to the mix, and we could see an SoC that overtakes the competition in graphics performance, though Economic News Daily has not mentioned this.

May 14, 2024

Tensor network decompositions for absolutely maximally entangled states

Posted by in categories: materials, quantum physics

Balázs Pozsgay and Ian M. Wanless, Quantum 8, 1339 (2024). Absolutely maximally entangled (AME) states of $k$ qudits (also known as perfect tensors) are quantum states that have maximal entanglement for all possible bipartitions of the sites/parties. We consider the problem of whether such states can be decomposed into a tensor network with a small number of tensors, such that all physical and all auxiliary spaces have the same dimension $D$. We find that certain AME states with $k=6$ can be decomposed into a network with only three 4-leg tensors; we provide concrete solutions for local dimension $D=5$ and higher. Our result implies that certain AME states with six parties can be created with only three two-site unitaries from a product state of three Bell pairs, or equivalently, with six two-site unitaries acting on a product state on six qudits. We also consider the problem for $k=8$, where we find similar tensor network decompositions with six 4-leg tensors.

May 14, 2024

BYD’s new electric hot hatch specs and name uncovered

Posted by in category: futurism

Key specs and name of BYD’s upcoming powerful electric hatchback have been revealed, including a faster top speed than the Seal.

May 14, 2024

Scientists create green composite material from Japanese washi paper

Posted by in categories: habitats, materials

Washi: the traditional Japanese paper, known for its beauty and strength, has been used in bookbinding, art, furniture, and architecture for hundreds of years. But, more recently, washi’s usage is on the decline, as people opt for more western style housing designs.

May 14, 2024

First sodium-ion battery storage station at grid level opens with cells that can be charged in 12 minutes

Posted by in category: energy

Clean electricity generation paired with the first grid-level sodium battery energy storage system can bring costs down to just $0.028 per kWh. The 10 MWh storage capacity is executed with sodium-ion cells that can be charged in just 12 minutes.

May 14, 2024

Electron vortices in graphene detected for the first time

Posted by in categories: materials, particle physics

When an ordinary electrical conductor—such as a metal wire—is connected to a battery, the electrons in the conductor are accelerated by the electric field created by the battery. While moving, electrons frequently collide with impurity atoms or vacancies in the crystal lattice of the wire, and convert part of their motional energy into lattice vibrations. The energy lost in this process is converted into heat that can be felt, for example, by touching an incandescent light bulb.

May 14, 2024

Scientists Discover a ‘Phonetic Alphabet’ Used by Sperm Whales, Moving One Step Closer to Decoding Their Chatter

Posted by in category: futurism

Sperm whales rattle off a series of rapid-fire clicks that researchers have named “codas.” Each coda consists of between three and 40 clicks. In addition to changing the number of clicks they make in quick succession, whales often speed up or slow down the tempo of each coda—researchers call this “rubato.” Sometimes, they add an extra “click” at the end of a coda, which scientists call “ornamentation.”

In the end, the team identified 156 distinct codas, each with its own rubato, ornamentation, tempo and rhythm. On their own, these codas may simply be meaningless sounds. But when combined, they could add up to something akin to syllables, words or even sentences.

Continue reading “Scientists Discover a ‘Phonetic Alphabet’ Used by Sperm Whales, Moving One Step Closer to Decoding Their Chatter” »

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