UNSW researchers have proposed a new way to distinguish between quantum bits that are placed only a few nanometres apart in a silicon chip, taking them a step closer to the construction of a large-scale quantum computer.
Quantum bits, or qubits, are the basic building blocks of quantum computers – ultra-powerful devices that will offer enormous advantages for solving complex problems.
Professor Michelle Simmons, leader of the research team, said a qubit based on the spin of an individual electron bound to a phosphorus atom within a silicon chip is one of the most promising systems for building a practical quantum computer, due to silicon’s widespread use in the microelectronics industry.
“However, to be able to couple electron-spins on single atom qubits, the qubits need to be placed with atomic precision, within just a few tens of nanometres of each other,” she says.
“This poses a technical problem in how to make them, and an operational problem in how to control them independently when they are so close together.”
The UNSW team, in collaboration with theorists at Sandia National Laboratories in New Mexico, has found a solution to both these problems. Their study is published in the journal Nature Communications.
In a significant feat of atomic engineering, they were able to read-out the spins of individual electrons on a cluster of phosphorus atoms that had been placed precisely in silicon. They also propose a new method for distinguishing between neighbouring qubits that are only a few nanometres apart.
“It is a daunting challenge to rotate the spin of each qubit individually,” says Holger Büch, lead author of the new study.
“But if each electron is hosted by a different number of phosphorus atoms, then the qubits will respond to different electromagnetic fields – and each qubit can be distinguished from the others around it,” he says.
The UNSW team is part of the Australian Centre of Excellence for Quantum Computation and Communication Technology, a world-leading research centre headquartered in Sydney, Australia.
“This is an elegant and satisfying piece of work,” says Professor Simmons, centre director and Mr Büch’s PhD supervisor.
“This first demonstration that we can maintain long spin lifetimes of electrons on multi-donor systems is very powerful. It offers a new method for addressing individual qubits, putting us one step closer to realising a practical, large-scale quantum computer.”
To make the tiny device, the researchers deposited a layer of hydrogen on a silicon wafer and used a scanning tunnelling microscope to create a pattern on the surface in an ultra-high vacuum.
This was then exposed to phosphine gas and annealed at 350 degrees so phosphorus atoms became incorporated precisely into the silicon. The device was then buried in another layer of silicon.
In a quantum computer information is stored in the spin, or magnetic orientation, of an electron. This spin can not only be in the two “classical” states – up and down – but also in a combination of both states at the same time, allowing exponentially larger amounts of information to be stored and processed in parallel.
An exciting and new water treatment breakthrough has been announced that will now make the removal of fluoride from the drinking water supplies of the world’s poorest people more affordable than ever.
Researchers from Rajasthan University in India have discovered that the Tulsi plant, also known as Holy Basil, can be used to significantly reduce the amount of fluoride in drinking water.
At present, the most reliable methods used to remove excessive fluoride from drinking water are either too expensive or not suitable for the environments where they are needed most.
The method discovered by researchers from Rajasthan University is safe, cheap and readily available, making it an ideal alternative for communities who can’t afford to use the more advanced techniques of removing fluoride that are readily available in the West.
An experiment was conducted in the Yellareddyguda village of Narketpally Mandal. The researchers soaked 75mg of Tulsi leaves in 100ml of water that contained 7.4 parts per million of fluoride in the water.
After only soaking the Tulsi leaves for eight hours, it was discovered that the level of fluoride in the water was reduced from 7.4 parts per million, to only 1.1 parts per million.
At present, the World Health Organization recommends that the safe level of fluoride in drinking water is between 0.5 to 1 parts per million.
The dangers of drinking water that contains high levels of fluoride are well known. Some of the known side effects of drinking water that contains fluoride are dental fluorosis, reduced intelligence in childrenand a damaged nervous system.
This new water treatment option could now provide the world’s poorest people an opportunity to remove excessive fluoride from their drinking water supplies.
However, more research is still needed to identify and validate the effectiveness of using Tulasi leaves as a means of removing fluoride from drinking water supplies.
Considering the cost-prohibitive nature of other more reliable water treatment techniques, if the Tulsi plant is conclusively proven to be effective in removing fluoride from drinking water, then we may witness a revolution in water treatment, providing options to areas where none currently exist.
- Recognition by the US Food and Drug Administration (FDA) that RLX030 has the potential to address a serious unmet medical need
- If approved, RLX030 has the potential to be the first treatment breakthrough for Acute Heart Failure patients in 20 years[1,2]
- RLX030 is the second Breakthrough Therapy designation by the FDA for Novartis investigational treatments, following LDK378
Novartis announced today that the US Food and Drug Administration (FDA) has granted Breakthrough Therapy designation status to RLX030 (serelaxin), an investigational treatment for patients with acute heart failure (AHF). The FDA has concluded that RLX030 qualifies for a Breakthrough Therapydesignation after considering the available clinical evidence which supports a substantial improvement over currently available therapies for AHF, a life-threatening illness.
The FDA’s decision was supported by efficacy and safety results from the phase III RELAX-AHF trial, which also showed that patients who received RLX030 had a 37% reduction in mortality at 6 months after an acute heart failure episode compared to those who received conventional treatment.
Each year around 3.5 million AHF episodes happen in the US and EU alone; this is expected to increase further as the population ages. Every AHF episode contributes to a downward spiral of worsening heart failure and damage to vital organs, such as the heart and kidneys, which decreases the chance of the patient surviving another episode. There is an urgent need for new treatments that help relieve patients’ symptoms and protect the vital organs against damage during an AHF episode, as well as have the potential to increase life expectancy in the AHF patient population.
“RLX030 is representative of Novartis’ strong commitment to develop innovative treatments for patients in areas of significant unmet need,” said David Epstein, Division Head of Novartis Pharmaceuticals. “Commonly used medicines for AHF only improve the immediate symptoms, so the additional effect on survival observed with RLX030 offers hope to patients and physicians”.
RLX030 is currently being assessed by health authorities around the world including the FDA and the European Medicines Agency (EMA) for the treatment of AHF.
About RLX030 and Novartis’ commitment to heart failure
RLX030 (serelaxin) is a form of a naturally occurring hormone (human relaxin-2), present in both men and women, although its levels rise in pregnant women to help the body cope with the additional cardiovascular demands during pregnancy. RLX030 is proposed for administration on admission to the emergency room to patients experiencing an AHF episode and is infused over a 48 hour period, in addition to conventional therapies.
In RELAX-AHF, RLX030 was shown to have both short and longer-term effects, helping patients breathe during and after an AHF episode, reducing the rate of heart failure worsening. Data from the clinical trial program has also shown that RLX030’s side effects are comparable to conventional therapy and it was generally well tolerated.
Another Novartis compound called LCZ696, an angiotensin receptor neprilysin inhibitor, is the first in a new class of dual acting drugs being evaluated for the treatment of chronic heart failure. A robust clinical development program including two global phase III studies (PARAGON-HF and PARADIGM-HF) is underway to fully assess the efficacy and safety profile of LCZ696.
About heart failure
Heart failure is a debilitating and potentially life-threatening condition where the heart cannot pump enough blood around the body. More than 15 million people suffer from heart failure globally and this number is increasing. The condition is often fatal when patients have one or repeated acute heart failure episodes. As an AHF episode approaches, patients become severely breathless and incapacitated and may rapidly gain weight due to fluid build-up in the lungs and around the body.
Patients experiencing an AHF episode need to be rushed to the emergency room for urgent treatment, making AHF the most common cause of hospitalization in patients over 65 years.
Source: Novartis newsletter.