System Bits: Feb. 7

Large scale quantum computer blueprint
An international team comprised of researchers from the University of Sussex, Google, Aarhus University, RIKEN, and Siegen University recently unveiled what they say is the first practical blueprint for how to build a quantum computer.

The team asserted that once built, the computer would have the potential to answer many questions in science; create new, lifesaving medicines; solve the most mind-boggling scientific problems; unravel the yet unknown mysteries of the furthest reaches of deepest space; and solve some problems that an ordinary computer would take billions of years to compute. This will be possible because of a new invention permitting actual quantum bits to be transmitted between individual quantum computing modules in order to obtain a fully modular large-scale machine capable of reaching nearly arbitrary large computational processing powers, they said.

Dr Bjorn Lekitsch (left) and Prof Winfried Hensinger behind a quantum computer prototype at the University of Sussex. (Source: University of Sussex)

And while scientists have previously proposed using fibre optic connections to connect individual computer modules, the new quantum computer blueprint introduces connections created by electric fields that allow charged atoms (ions) to be transported from one module to another in order to enable 100,000 times faster connection speeds between individual quantum computing modules compared to current state-of-the-art fibre link technology.

Professor Winfried Hensinger, head of the Ion Quantum Technology Group at the University of Sussex, who has been leading this research said for many years, people said that it was completely impossible to construct an actual quantum computer. “With our work we have not only shown that it can be done but now we are delivering a nuts and bolts construction plan to build an actual large-scale machine.”

As a next step, the team will construct a prototype quantum computer, based on this design, at the University of Sussex.

Looking for entangled atoms
In a development that is meant to move scientists closer to an elusive entangled state that would have potential sensing and computing applications beyond its basic science interests, Georgia Tech researchers have observed a sharp magnetically-induced quantum phase transition where they expect to find entangled atomic pairs using a Bose-Einstein condensate composed of millions of sodium atoms.

The researchers said the use of entangled atoms from a condensate could improve the sensitivity, and reduce the noise in sensing very small changes in physical properties such as magnetic fields or rotation. It could also provide a foundation for quantum computers able to perform certain calculations much faster than conventional digital computers. 

Photo shows equipment used for observing entangled Bose-Einstein condensates. (Source: Georgia Tech)

Chandra Raman, an associate professor in the Georgia Tech School of Physics and former graduate student Anshuman Vinit have been studying Bose-Einstein condensates (BECs) as a source of entanglement, seeking to take advantage of the system’s quantum purity to create conditions where correlation between atoms might occur. BECs don’t normally contain entangled atoms.
 
“We found ways to engineer the system to create entanglement,” Raman explained. “We looked at the behavior of the system as we tuned the magnetic field very close to the phase boundary and showed that the boundary had a very sharply defined point. We were able to resolve that boundary with a level of uncertainty we didn’t think we could get until we did the experiment.”

Interestingly, while theoretical predictions suggested that at the boundary between different magnetic phases of a spinor Bose-Einstein condensate, scientists would find an entangled quantum state of all the atoms, in spinor Bose-Einstein condensates, the individual magnetic moments do not need to have a well-defined orientation in space, but rather, can exist in a superposition of different orientations.

Though the researchers said they haven’t yet observed that entangled state yet, their work so far has defined an experimental window within which to look for new physical effects governing different magnetic phases, or to generate entangled states that are relevant for quantum-based systems.

They believe they’ve set the stage for observing entanglement in a smaller groups of atoms, perhaps no more than a thousand. Once that’s shown, the large ensemble of atoms could be broken down into many smaller groups operating independently, each with phase boundaries containing entangled atoms.
 

Stomach acid powered sensors
Researchers at MIT and Brigham and Women’s Hospital have designed and demonstrated a small voltaic cell that is sustained by the acidic fluids in the stomach. The system can generate enough power to run small sensors or drug delivery devices that can reside in the gastrointestinal tract for extended periods of time. They believe this type of power could offer a safer and lower-cost alternative to the traditional batteries now used to power such devices.

Researchers at MIT and Brigham and Women’s Hospital have designed and demonstrated a small, ingestible voltaic cell that is sustained by the acidic fluids in the stomach.
(Source: MIT)

The research team took inspiration from a very simple type of voltaic cell known as a lemon battery, which consists of two electrodes — often a galvanized nail and a copper penny — stuck in a lemon. The citric acid in the lemon carries a small electric current between the two electrodes.
To replicate that strategy, the researchers attached zinc and copper electrodes to the surface of their ingestible sensor. The zinc emits ions into the acid in the stomach to power the voltaic circuit, generating enough energy to power a commercial temperature sensor and a 900-megahertz transmitter.

This development could lead to a self-powered pill that would monitor vital signs from inside for a couple of weeks. Such devices could also be used for drug delivery. In this study, the researchers demonstrated that they could use the power generated by the voltaic cell to release drugs encapsulated by a gold film. This could be useful for situations in which doctors need to try out different dosages of a drug, such as medication for controlling blood pressure.