For faster battery charging, try a quantum battery?

August 3, 2015 by Lisa Zyga feature
(A) An array of qubits can be charged either (B) in parallel or (C) globally. The results show that, when global entangling operations are allowed on the array during charging, the charging rate increases as the number of qubits increases. Credit: Binder, et al. CC-BY-4.0

(—Physicists have shown that a quantum battery—basically, a quantum system such as a qubit that stores energy in its quantum states—can theoretically be charged at a faster rate than conventional batteries. This "quantum speedup" arises from quantum entanglement among multiple qubits, which essentially provides a shortcut between the qubits' uncharged and charged states, allowing for faster charging.

The physicists, Felix C. Binder, et al., have published a paper on the , which they call "quantacell," in a recent issue of the New Journal of Physics.

"There has been much interest in the question if can provide any advantage in thermodynamic processes (thermodynamics being the study of work and heat and their interconversion)," Binder, a physicist at the University of Oxford, told "Our paper demonstrates with an example that a significant advantage can indeed be achieved when a short process duration is desired—quantum correlations ('quantum entanglement') can lead to a significant speedup."

The scientists investigated a quantum battery made of , which can take a variety of physical forms, such as ions, neutral atoms, photons, etc. Qubits can exist in either one of two states or a superposition of both states at once. In a quantum battery, the two states represent different energy levels. Charging a quantum battery means changing a qubit's state from a lower energy level to a higher energy level, while using (discharging) the battery does the reverse. The scientists call these particular qubits "work qubits" (or simply "wits") because they can store energy that can later be used to do work.

A Bloch Sphere showing the “cone of states” that achieve maximum average power, i.e., the fastest charging time. The quantum speedup is due to the shorter distance that has to be traveled between states when entangling is permitted. Credit: Binder, et al. CC-BY-4.0

So far, this description is similar to how a conventional battery works. However, the important difference is that, as quantum systems, qubits may be entangled, meaning the qubits are so strongly correlated that an entire qubit array can be described by the same quantum state. Here, the researchers have shown that one consequence of entangling the qubits during the charging process is that it means a shorter distance has to be traveled through state space—that is, between the low and high energy states—than would be required without entanglement.

The scientists showed that, the more qubits, and hence the more entanglement, the faster the charging process. In the example protocol, the charging time is inversely proportional to the number of qubits. So hypothetically, if one work qubit took an hour to charge, six work qubits could be charged in 10 minutes. In reality, however, typical quantum systems cannot remain quantum for anywhere near this length of time due to decoherence—interactions with the surrounding environment that destroy the quantum effects.

Besides decoherence, another roadblock to using quantum batteries for real-life applications is that the amount of energy that they can store is tiny compared to the energy needs of, for example, mobile phones or electric vehicles.

"The energies of quantum systems tend to be many orders of magnitude smaller than even the smallest energies used by day-to-day appliances," explained coauthor John Goold, a physicist at The Abdus Salam International Centre for Theoretical Physics in Trieste, Italy. "'Size' is here a question of energy scales. Our study is a theoretical proof-of-principle that quantum physics can provide a speedup in depositing energy into a system. These speedup effects would be relevant in two cases: 1) Mechanical devices become small enough that energy scales are comparable to current implementations of . 2) Quantum systems are scaled up and robustly controllable at energy scales that are of practical importance."

To better understand the potential applications of quantum batteries, the researchers plan to further investigate the quantum effects of thermodynamic processes. The big question is, can a quantum battery produce work (directed energy) rather than simply heat (disordered energy)?

"What we call 'quantum batteries' in the paper exists in labs: Any controllable quantum system with stable energy eigenstates can be understood as a battery," Binder said. "The question is rather if the thermodynamic viewpoint will be helpful for quantum experiments with systems like ions, cold neutral atoms (for instance, on an optical lattice), condensed matter systems (for example, superconducting qubits and circuit quantum electrodynamics), or light."

Explore further: Flying qubits make for a highly resilient quantum memory

More information: Felix C. Binder, et al. "Quantacell: powerful charging of quantum batteries." New Journal of Physics. DOI: 10.1088/1367-2630/17/7/075015

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not rated yet Aug 03, 2015
Sometimes low tech is smartest. I get my cell's battery recharged in 15 seconds. I bought a dead one on the 'net for 50 cents and use it to recharge the battery. Swap batteries, 15 seconds later I have a fully charged battery.

lol After years of taking money to molly-coddle trolls they've got out and out spammers now! Is there a moderator? Will that, even, be deleted? Let's see. Fucking scammers using a Panamanian company to obscure their identity...but trust us. Are people REALLY that stupid? Well, yeah, since they target stay-at-home frauds, proud of their environmental terrorism, I guess they could believe anything. "One *weird* old trick for separating idiots from their cash..."
not rated yet Aug 03, 2015
How about Entangling Brains of Cockroaches...Make them all go hungry en masse!
not rated yet Aug 03, 2015
Swap batteries, 15 seconds later I have a fully charged battery.

Handy - until you accidentally put the spare battery through the washing because you forgot it in your pocket. Your results may vary, mine ended up in smoke.

The main problem is that you need a stand-alone charger for the spare battery, which you then have to lug along wherever you go because you can't charge bare cells directly from USB. You simply trade the inconvenience of recharging the cellphone with the inconvenience of recharging the spare cell - plus the fact that you have to turn off and dismantle your phone to get at the battery in the first place.

not rated yet Aug 03, 2015
Are people REALLY that stupid?

No, but we do stupid things. Fortunately for us, our actions do not define us. And when someone comes along and attempts to define us as something we are not, even if we do not logically understand that we are most important in that moment, we still are, here, living with what really is true. In a nut shell, "you" have told a lie, whether "you" realize it or not.

Now "you" want to call for censorship? How about "you" take more care in what "you" say and stop trying to hold everyone up with censorship because "you" haven't learned yet that everyone at their core can tell that "you" have lied. That's "you" doing that.

It's not a secret. Tell the truth. Choose to live with compassion and honesty. All the rest has a truthful possibility to follow. It's a work in progress for us all.
not rated yet Aug 03, 2015
The truth defines us as "most important". Anything less cannot be true.

How big is "most important"? We tend to underestimate how important "most important" actually is. Failing to the get what is most important correct while developing the possible technologies with quantum states together with all the other things that don't seem to have short term practical use other than, "that's strange", might yield a terrible danger to life, because it is life that is most important in life.

We certainly have our work before us.
1 / 5 (1) Aug 04, 2015
Are people REALLY that stupid?

That from someone who believes in god? Very thin ice, dude...very thin.

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