Quantum Cryptography communication may not be secure for more than one use

Arxiv- Prisoners of their own device: Trojan attacks on device-independent quantum cryptography (7 pages)

Device-independent cryptographic schemes aim to guarantee security to users based only on the output statistics of any components used, and without the need to verify their internal functionality. Since this would protect users against untrustworthy or incompetent manufacturers, sabotage or device degradation, this idea has excited much interest, and many device-independent schemes have been proposed. We point out here a critical weakness of device-independent quantum cryptography for tasks, such as key distribution, that rely on public communication between secure laboratories. Untrusted devices may record their inputs and outputs and reveal encoded information about them in their outputs during later runs. Reusing devices thus compromises the security of a protocol and risks leaking secret data. Possible solutions include securely destroying used devices or isolating them until previously generated data need no longer be kept secret. However, such solutions are costly and impose severe constraints on the practicality of many device-independent quantum cryptographic schemes.

UK sets sights on gene therapy in embryos

Nature - Public consultation and safety assessment would pave the way for embryo manipulation to treat genetic diseases.

Britain has set out a road map towards the first clinical tests of reproductive techniques that combine parents’ genes with DNA from a third party. The approach raises ethical questions, but could spare children from inheriting some rare diseases, including forms of muscular dystrophy and neurodegenerative disorders that affect around 1 in 5,000 people.

These conditions are caused by defects in the mitochondria, the ‘power packs’ of the cell, which are inherited from a child’s mother through the egg. Experiments on primates, and with defective human eggs, have already shown that genetic material can be removed from an egg that has faulty mitochondria and transferred to a healthy donor ovum, leaving the flawed mitochondrial DNA behind. In principle, the resulting egg could then develop into a healthy child carrying both the parents’ nuclear genes and mitochondrial DNA from the donor. But the work amounts to genetic modification of embryos — which is currently illegal in the United Kingdom — and also involves destroying fertilized eggs.

Cool Nano Loudspeakers Could Make for Better MRIs, Quantum Computers

NIST - A team of physicists from the Joint Quantum Institute (JQI), the Neils Bohr Institute in Copenhagen, Denmark, and Harvard University has developed a theory describing how to both detect weak electrical signals and cool electrical circuits using light and something very like a nanosized loudspeaker.* If demonstrated through experiment, the work could have a tremendous impact on detection of low-power radio signals, magnetic resonance imaging (MRI), and the developing field of quantum information science.

"We envision coupling a nanomechanical membrane to an electrical circuit so that an electrical signal, even if exceedingly faint, will cause the membrane to quiver slightly as a function of the strength of that signal," says JQI physicist Jake Taylor. "We can then bounce photons from a laser off that membrane and read the signal by measuring the modulation of the reflected light as it is shifted by the motion of the membrane. This leads to a change in the wavelength of the light."

JQI researchers think they have discovered a way to amplify faint electrical signals using the motion of a nanomechanical membrane, or loudspeaker. If shown in experiments, the scheme could prove a boon to magnetic resonance imaging and quantum information science. This schematic of the proposed device shows its use in detecting--in this example--a signal produced by the quantum-mechanical "spin" of a group of atoms. The atoms generate a faint radiofrequency signal in a coil (L) which is connected to microscale wires that form an electrical capacitor. This vibrates the 'nanomembrane' which in turn affects the resonant frequency of a laser optical cavity. The output is light at frequency that is the sum of the original laser frequency plus the signal from the atoms.
Credit: Taylor/NIST

Physical Review Letters - Laser Cooling and Optical Detection of Excitations in a LC Electrical Circuit

1000 times less energy to produce the microbubbles which can be used in Algae Biofuel Production

A solution to the difficult issue of harvesting algae for use as a biofuel has been developed using microbubble technology pioneered at the University of Sheffield. The technique builds on previous research in which microbubbles were used to improve the way algae is cultivated.

Algae produce an oil which can be processed to create a useful biofuel. Biofuels, made from plant material, are considered an important alternative to fossil fuels and algae, in particular, has the potential to be a very efficient biofuel producer. Until now, however, there has been no cost-effective method of harvesting and removing the water from the algae for it to be processed effectively.

Now, a team led by Professor Will Zimmerman in the Department of Chemical and Biological Engineering at the University of Sheffield, believe they have solved the problem. They have developed an inexpensive way of producing microbubbles that can float algae particles to the surface of the water, making harvesting easier, and saving biofuel-producing companies time and money. The research is set to be published in Biotechnology and Bioengineering on 26 January 2012.

The system developed by Professor Zimmerman´s team uses up to 1000 times less energy to produce the microbubbles and, in addition, the cost of installing the Sheffield microbubble system is predicted to be much less than existing flotation systems.

Cardiac muscle cells have been loaded onto a 3D silk scaffold

Damaged human heart muscle cannot be regenerated. Scar tissue grows in place of the damaged muscle cells. Scientists from the Max Planck Institute for Heart and Lung Research in Bad Nauheim are seeking to restore complete cardiac function with the help of artificial cardiac tissue. They have succeeded in loading cardiac muscle cells onto a three-dimensional scaffold, created using the silk produced by a tropical silkworm. It is a step down a long road towards creating a tissue for repairing damaged hearts.

At the university there, coin-sized disks are being produced from the cocoon of the tasar silkworm (Antheraea mylitta). According to Chinmoy Patra, an Indian scientist who now works in Engel’s laboratory, the fibre produced by the tasar silkworm displays several advantages over the other substances tested. “The surface has protein structures that facilitate the adhesion of heart muscle cells. It’s also coarser than other silk fibres.” This is the reason why the muscle cells grow well on it and can form a three-dimensional tissue structure. “The communication between the cells was intact and they beat synchronously over a period of 20 days, just like real heart muscle,” says Engel.

Despite these promising results, clinical application of the fibre is not currently on the agenda. “Unlike in our study, which we carried out using rat cells, the problem of obtaining sufficient human cardiac cells as starting material has not yet been solved,” says Engel. It is thought that the patient’s own stem cells could be used as starting material to avoid triggering an immune reaction. However, exactly how the conversion of the stem cells into cardiac muscle cells works remains a mystery.

Disks cut from the cocoon of the tasar silkworm grub provide a basic scaffold for heart muscle

Physicists Measure Propagation Velocity of Quantum Signals in a Many-Body System

Science Daily - Physicists at the Max Planck Institute of Quantum Optics have measured the propagation velocity of quantum signals in a many-body system. A quantum computer based on quantum particles instead of classical bits, can in principle outperform any classical computer. However, it still remains an open question, how fast and how efficient quantum computers really may be able to work. A critical limitation will be given by the velocity with which a quantum signal can spread within a processing unit.

The communication and processing of information in a quantum computer is based on concepts that are inherently different from those used in classical computers. This is due to the fundamental differences between quantum particles and classical objects. Whereas the latter are, for example, either black or white, quantum particles can take on both colours at the same time. It is only at the process of measurement that the particles decide on one of the two possible properties. As a consequence of this peculiar behaviour, two quantum objects can form one entangled state in which their properties are strictly connected, i.e. quantum correlated. At present there is no general model for predicting how fast a quantum correlation can travel after it is generated.

Propagation of quantum correlations in an optical lattice. Left: artist’s view (Graphic by woogie works animation studio). Right: a) In the initial state, each lattice site is filled by exactly one atom. The height of the barrier between the sites is then abruptly lowered, bringing the system out of equilibrium. b) After the barrier has been lowered, an entangled doublon-holon pair is formed. The correlated doublons and holons move across the system with opposite momenta. (Credit: MPQ)


Nature - Light-cone-like spreading of correlations in a quantum many-body system

China’s Provincial GDP Figures in 2011 and forecasts for 2012 through 2015

China Briefing - 2011 Provincial GDP figures

Wikipedia GDP per capita by province in China.

Jiangsu Province’s GDP grew 9.2 percent to RMB4.8 trillion (US$759 billion) in 2011, according to the provincial government’s report. Jiangsu’s GDP per capita reached US$9,500.

In 2012, Jiangsu (80 million), Zhejiang (56 million), Inner Mongolia (25 million) should be over US$10,000 GDP per capita. They will join Shanghai (23 million), Beijing (20 million), and Tianjin (13 million) with GDP per capita over US$10,000.

Liaoning (44 million) and Guangdong (105 million) should get over the US$10,000 per capita level in 2013. Shandong (96 million) and Fujian (37 million) should get over the US$10,000 per capita level in 2013 or 2014.

Getting over US$12,000 per person in 2010 dollars is the level where a country is believed to exceeded the level of a middle income trap.

Shanghai, Beijing and Tianjin are all over the US$12,000 per capita level as of the end of 2011. The other provinces should clear the US$12,000 per capita levels 1 to 2 years after they clear the US$10,000 per capita levels.

By 2015, China should have provinces with a combined population of about 500 million with per capita GDP over US$12,000. I am projecting all of China to have a per capita GDP of about $9000-10000 in 2010 US dollars in 2015