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Category: quantum physics – Page 349

Optical phase retrieval and imaging appear in a wide variety of science fields, such as imaging of quasi-transparent biological samples or nanostructures metrological characterization, for example, in the semiconductor industry. At a fundamental level, the limit to imaging accuracy in classical systems comes from the intrinsic fluctuation of the illuminating light, since the photons that form it are emitted randomly by conventional sources and behave independently of one another.

Quantum correlation in light beams, in which photons show certain cooperation, can surpass those limits. Although obtained in phase estimation through first-order interference is well understood, interferometric schemes are not suitable for multi-parameter wide-field imaging, requiring raster scanning for extended samples.

In a new paper published in Light Science & Application, a team of scientists from the Quantum Optics Group of the Italian National Metrology Institute (INRiM), Italy, and from the Imaging Physics Dept. Optics Research Group, Faculty of Applied Sciences of Delft University of Technology, The Netherlands, has developed a technology exploiting quantum correlations to enhance imaging of phase profiles in a non-interferometric way.

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Physical interpretations of the time-symmetric formulation of quantum mechanics, due to Aharonov, Bergmann, and Lebowitz are discussed in terms of weak values. The most direct, yet somewhat naive, interpretation uses the time-symmetric formulation to assign eigenvalues to unmeasured observables of a system, which results in logical paradoxes, and no clear physical picture. A top–down ontological model is introduced that treats the weak values of observables as physically real during the time between pre-and post-selection (PPS), which avoids these paradoxes. The generally delocalized rank-1 projectors of a quantum system describe its fundamental ontological elements, and the highest-rank projectors corresponding to individual localized objects describe an emergent particle model, with unusual particles, whose masses and energies may be negative or imaginary. This retrocausal top–down model leads to an intuitive particle-based ontological picture, wherein weak measurements directly probe the properties of these exotic particles, which exist whether or not they are actually measured.

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Researchers at the National Institute of Standards and Technology (NIST) have devised a photonic circuit on a chip that transforms a single incoming beam of laser light into a panoply of new beams, each with a host of different optical properties.

The newly generated beams—which retain the frequency of the original beam—simultaneously exit the circuit at different locations along the . That allows scientists and engineers to select the specific characteristics of one or more beams needed for a particular application.

Precision shaping and controlling beams of visible light are critical for diagnosing and studying human diseases, trapping atoms that form the basis of the world’s most , quantum computing, and many other quantum-based technologies.

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Quantum memory that depends on quantum-band integration is a key building block used to develop quantum networks that are compatible with fiber communication infrastructures. Quantum engineers and IT specialists have yet to create such a network with large capacity to form an integrated multimode photonic quantum memory at telecom band.

In a new report in Science Advances, Xueying Zhang and a research team in electronic science, physics, and information technology described fiber-integrated multimode storage of a single photon at telecom band on a laser-written chip.

The storage device made of fiber-pigtailed erbium (Er3+) doped lithium niobate (Er3+:LiNbO3), presented a memory system integrated with telecom-band fiber-integrated on-chip components. The outcomes of the study highlight a pathway for future to come in to being, based on integrated photonics devices.

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Many substances change their properties when they are cooled below a certain critical temperature. Such a phase transition occurs, for example, when water freezes. However, in certain metals there are phase transitions that do not exist in the macrocosm. They arise because of the special laws of quantum mechanics that apply in the realm of nature’s smallest building blocks.

It is thought that the concept of electrons as carriers of quantized no longer applies near these exotic transitions. Researchers at the University of Bonn and ETH Zurich have now found a way to prove this directly. Their findings allow new insights into the exotic world of quantum physics. The publication has now been released in the journal Nature Physics.

If you below zero degrees Celsius, it solidifies into ice. In the process, it abruptly changes its properties. As ice, for example, it has a much lower density than in a liquid state—which is why icebergs float. In physics, this is referred to as a phase transition.

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A long-standing challenge in the field of quantum physics is the efficient synchronization of individual and independently generated photons (i.e., light particles). Realizing this would have crucial implications for quantum information processing that relies on interactions between multiple photons.

Researchers at Weizmann Institute of Science recently demonstrated the synchronization of single, independently generated photons using an atomic quantum memory operating at room-temperature. Their paper, published in Physical Review Letters, could open new avenues for the study of multi-photon states and their use in .

“The project idea came about several years ago, when our group and the group of Ian Walmsley demonstrated an atomic quantum memory with an inverted atomic-level scheme compared to the typical memories—the ladder memory, named fast ladder memory (FLAME),” Omri Davidson, one of the researchers who carried out the study, told Phys.org. “These memories are fast and noise-free, and therefore they are useful for synchronization of single photons.”

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