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Related News: Quantum Control Measurement and Sensing

In Schrödinger's famous thought experiment, a cat seems to be both dead and alive—an idea that strains credulity. These days, cats still don't act this way, but physicists now regularly create analogues of Schrödinger's cat in the lab by smearing the microscopic quantum world over longer and longer distances.
Such "cat states" have found many homes, promising more sensitive quantum...

Optical fibers are ubiquitous, carrying light wherever it is needed. These glass tunnels are the high-speed railway of information transit, moving data at incredible speeds over tremendous distances. Fibers are also thin and flexible, so they can be immersed in many different environments, including the human body, where they are employed for illumination and imaging.Physicists use fibers, too...

In an arranged marriage of optics and mechanics, JQI-NIST physicists have created microscopic structural beams that have a variety of powerful uses when light strikes them. Able to operate in ordinary, room-temperature environments, yet exploiting some of the deepest principles of quantum physics, these optomechanical systems can act as inherently accurate thermometers, or conversely, as a...

Optical fibers are the backbone of modern communications, shuttling information from A to B through thin glass filaments as pulses of light. They are used extensively in telecommunications, allowing information to travel at near the speed of light virtually without loss.These days, biologists, physicists and other scientists regularly use optical fibers to pipe light around inside their labs....

When is a traffic jam not a traffic jam? When it's a quantum traffic jam, of course. Only in quantum physics can traffic be standing still and moving at the same time. A new theoretical paper from scientists at the National Institute of Standards and Technology (NIST) and the University of Maryland suggests that intentionally creating just such a traffic jam out of a ring of several thousand...

From credit card numbers to bank account information, we transmit sensitive digital information over the internet every day. Since the 1990s, though, researchers have known that quantum computers threaten to disrupt the security of these transactions. That’s because quantum physics predicts that these computers could do some calculations far faster than their conventional counterparts. This...

For the first time, a team including scientists from the National Institute of Standards and Technology (NIST) and JQI have used neutron beams to create holograms of large solid objects, revealing their interior details in ways that ordinary holograms do not.Holograms—flat images that look like three-dimensional objects—owe their striking look to interfering waves. Both matter and light behave...

Today’s networks use electronic circuits to store information and optical fibers to carry it, and quantum networks may benefit from a similar framework. Such networks would transmit qubits – quantum versions of ordinary bits – from place to place and would offer unbreakable security for the transmitted information. But researchers must first develop ways for qubits that are better at storing...

Harnessing quantum systems for information processing will require controlling large numbers of basic building blocks called qubits. The qubits must be isolated, and in most cases cooled such that, among other things, errors in qubit operations do not overwhelm the system, rendering it useless. Led by JQI Fellow Christopher Monroe, physicists have recently demonstrated important steps towards...

The concept of temperature is critical in describing many physical phenomena, such as the transition from one phase of matter to another. Turn the temperature knob and interesting things can happen. But other knobs might be just as important for studying some phenomena. One such knob is chemical potential, a thermodynamic parameter first introduced in the nineteenth century by scientists for...

From NIST-PML — Precise measurements of optical power enable activities from fiber-optic communications to laser manufacturing and biomedical imaging — anything requiring a reliable source of light. This situation calls for light-measuring (radiometric) standards that can operate over a wide range of power levels.

Currently, however, different methods for calibrating...

Experimental quantum physics often resides in the coldest regimes found in the universe, where the lack of large thermal disturbances allows quantum effects to flourish. A key ingredient to these experiments is being able to measure just how cold the system of interest is. Laboratories that produce ultracold gas clouds have a simple and reliable method to do this: take pictures! The...

Optical fibers are hair-like threads of glass used to guide light. Fibers of exceptional purity have proved an excellent way of sending information over long distances and are the foundation of modern telecommunication systems. JQI researchers in collaboration with scientists from the Naval Research Laboratory have developed a new technique for visualizing light propagation through an optical...

In another advance at the far frontiers of timekeeping by National Institute of Standards and Technology (NIST) researchers, the latest modification of a record-setting strontium atomic clock has achieved precision and stability levels that now mean the clock would neither gain nor lose one second in some 15 billion years*—roughly the age of the universe. Precision timekeeping has broad...

UMD will honor nine nominees for the most promising new inventions at the Celebration of Innovation and Partnerships event on April 29, 2015. UMD’s Office of Technology Commercialization, part of the Division of Research, received a total of 187 disclosures in 2014. The nine nominees for...

The word “defect” doesn’t usually have a good connotation--often indicating failure. But for physicists, one common defect known as a nitrogen-vacancy center (NV center) has applications in both quantum information processing and ultra-sensitive magnetometry, the measurement of exceedingly faint magnetic fields. In an experiment, recently published in Science, JQI...

The 2014 chemistry Nobel Prize recognized important microscopy research that enabled greatly improved spatial resolution. This innovation, resulting in nanometer resolution, was made possible by making the source (the emitter) of the illumination  quite small and by moving it quite close to the object being imaged.   One problem with this approach is that in such proximity, the emitter and...

Measuring faint magnetic fields is a trillion-dollar business.  Gigabytes of data, stored and quickly retrieved from chips the size of a coin, are at the heart of consumer electronics.   Even higher data densities can be achieved by enhancing magnetic detection sensitivity---perhaps down to nano-tesla levels.

Greater magnetic sensitivity is also useful in many scientific areas, such as...

 A new experiment conducted at the University of California at Berkeley used quantum information techniques for a precision test of a cornerstone principle of physics, namely Lorentz invariance.  This precept holds that the results of a physics experiment do not depend on its absolute spatial orientation.  The work uses quantum-correlated electrons within a pair of calcium ions to look for...

Alan Migdall and Elohim Becerra and their colleagues at the Joint Quantum Institute have devised an optical detection scheme with an error rate 25 times lower than the fundamental limit of the best conventional detector. They did this by employing not passive detection of incoming light pulses. Instead the light is split up and measured numerous times.

Interfering Waves

A new extreme for sub-wavelength interference has been achieved by JQI scientists using thermal light and small-photon-number light detection. Achieving this kind of sharp interference pattern could be valuable for performing a variety of high-precision physics and astronomy measurements.

JQI scientists have added an important technique to the atomtronics arsenal, a method for analyzing a superfluid circuit component called a ‘weak link’. The result, detailed in the online journal Physical Review X, is the first direct measurement of the current-phase relationship of a weak link in a cold atom system.

Atomtronics is an emerging technology whereby physicists use ensembles of atoms to build analogs to electronic circuit elements. Modern electronics relies on utilizing the charge properties of the electron. Using lasers and magnetic fields, atomic systems can be engineered to have behavior analogous to that of electrons, making them an exciting platform for studying and...