Quantum measurement theory. Medical search. Frequent questions

This is a central feature of quantum mechanics, one that is both mathematically intricate and conceptually subtle. (wikipedia.org)
In quantum mechanics, each physical system is associated with a Hilbert space, each element of which represents a possible state of the physical system. (wikipedia.org)
Quantum mechanics is a probabilistic theory that does not describe individual events. (sciencedaily.com)
This apparent contradiction, known as the measurement problem, has a long history going back to the early days of quantum mechanics. (sciencedaily.com)
Understanding the quantum measurement process requires describing the measured system and the measurement apparatus as a compound quantum system governed by the rules of quantum statistical mechanics. (sciencedaily.com)
The formalism of quantum mechanics assigns numbers called 'q-probabilities' to each possible outcome of an arbitrary measurement. (sciencedaily.com)
May 14, 2021 Quantum mechanics is famous for its indeterminism, but we can usually use probabilities to quantify our uncertainty about future observations. (sciencedaily.com)
In this paper we continue the line of investigation 7 of probing the foundations of quantum mechanics through apparent quantum paradoxes. (nature.com)
The result resolves long-standing open problems in the foundations of quantum mechanics (Tsirelson's problem) and operator algebras (Connes' embedding problem). (acm.org)
He has published on a wide range of topics in quantum mechanics including atom interferometry, quantum optics, Heisenberg limited interferometry, superradiance, ultra-cold gas dynamics, trapped-ion physics, dynamical decoupling and quantum weak measurement. (sun.ac.za)
Topos theory and quantum mechanics are both known for having a logic that is different from ordinary logic. (tudelft.nl)
Unlike other conspiracy theories, such as Hollow earth , Men In Black, cattle mutilation, UFO , Reich & Tesla or what have you, the INCUNABULA Theory harmonizes with genuine frontier quantum mechanics and chaos mathematics, and does not depend on any quack nostrums, psuedoscience or ESP for proof. (incunabula.org)
Bell's Theorem and Inequalities pointed the way to the many physical experiments that have confirmed the standard model of quantum mechanics, but Bell and others were never satisfied that standard quantum mechanics could "explain" what is "really" going on in the microscopic world (despite the extraordinary accuracy of the theory). (informationphilosopher.com)
The most famous proposal for a solution to these mysteries was Albert Einstein 's original criticism that quantum mechanics was "incomplete" and that additional information was needed to restore his intuition of "local reality. (informationphilosopher.com)
The GRW scheme represents a proposal aimed to overcome the difficulties of quantum mechanics discussed by John Bell in his article "Against Measurement. (informationphilosopher.com)
Jeremy Nicholas Butterfield FBA (born 1954) is a philosopher at the University of Cambridge , noted particularly for his work on philosophical aspects of quantum theory , relativity theory and classical mechanics . (wikipedia.org)
He has also made several appeals in his work, on classical mechanics and other physical theories, to the importance of an appreciation of modality in physics. (wikipedia.org)
Interestingly, however, quantum mechanics permits building QKD protocols using devices called quantum repeaters, which if supplied at the relay nodes, would make it unnecessary to physically secure them, thus enabling long-distance high-rate QKD. (nature.com)
This is where the name Many Worlds comes from-the "Many Worlds" interpretation of quantum mechanics is a theory by Hugh Everette which states that quantum wave function collapse is actually the superposition of quantum states built by the decoherence of independent wave functions. (motorcityguitar.com)
This is a new volume of original essays on the metaphysics of quantum mechanics. (philpapers.org)
The essays address questions such as: What fundamental metaphysics is best motivated by quantum mechanics? (philpapers.org)
Does quantum mechanics support the existence of any other fundamental entities, e.g. particles? (philpapers.org)
What is the nature of the fundamental space of quantum mechanics? (philpapers.org)
What is the relationship between the fundamental ontology of quantum mechanics and ordinary, macroscopic objects like tables, chairs, and persons? (philpapers.org)
This collection includes a comprehensive introduction with a history of quantum mechanics and the debate over its metaphysical interpretation focusing especially on the main realist alternatives. (philpapers.org)
Quantum Mechanics and the Nature of Reality. (philpapers.org)
Philosophical Materialism and the Many-Worlds Interpretation of Quantum Mechanics. (philpapers.org)
Quantum mechanics without wave functions. (philpapers.org)
Quantum Mechanics in a Time-Asymmetric Universe: On the Nature of the Initial Quantum State. (philpapers.org)
This celebrated theorem - loved by some and hated by others - shows that correlations in quantum mechanics can be stronger than in theories with local hidden variables. (blogspot.com)
Such local hidden variables theories are modifications of quantum mechanics which aim to stay close to the classical, realist picture, and promise to make understandable what others have argued cannot be understood. (blogspot.com)
In these substitutes for quantum mechanics, the 'hidden variables' serve to explain the observed randomness of quantum measurement. (blogspot.com)
Experiments show however that correlations can be stronger than local hidden variables theories allow, as strong as quantum mechanics predicts. (blogspot.com)
This is very clear evidence against local hidden variables, and greatly diminishes the freedom researchers have to play with the foundations of quantum mechanics. (blogspot.com)
I like superdeterministic hidden variable theories because they stay as close to quantum mechanics as possible while not buying into fundamental non-determinism. (blogspot.com)
Albert Einstein wasn't entirely convinced about quantum mechanics, suggesting our understanding of it was incomplete. (sciencealert.com)
The test proposes a mathematical inequality which, if broken, shows that the theory of quantum mechanics holds together. (sciencealert.com)
Despite the challenges of constructing and fine-tuning the machine, the researchers are confident that it could be adapted to work on larger scales, too, pushing the boundaries of what we know about quantum mechanics. (sciencealert.com)
Measurement-collapse interpretations of quantum mechanics [MCIs] take the orthodox textbook formulation of quantum mechanics literally. (cam.ac.uk)
For his contributions to laser science and tests of fundamental physical principles, in particular the application of ultra-stable lasers to tests of quantum measurement theory and the fundamentals of quantum mechanics. (aps.org)
The physical content of quantum kine-matics and mechanics. (bvsalud.org)
The general aim of the course is that students after completed course should have acquired knowledge and skills in the basic quantum mechanics that are needed for continued studies of quantum physics. (lu.se)
The course covers basic quantum mechanics. (lu.se)
In spite of being the first testing ground of Quantum Mechanics, almost hundred years ago, Atomic Structure Theory is a vibrant and active area. (lu.se)

In quantum physics, a measurement is the testing or manipulation of a physical system to yield a numerical result. (wikipedia.org)
Quantum physics has proven to be an empirical success and to have wide-ranging applicability. (wikipedia.org)
The dimension of the Hilbert space may be infinite, as it is for the space of square-integrable functions on a line, which is used to define the quantum physics of a continuous degree of freedom. (wikipedia.org)
In a paper published in Annals of Physics in January, the researchers propose two main ingredients that are sufficient to account for all properties of quantum measurements, including the uniqueness of the outcome of each individual run. (sciencedaily.com)
Approved For Release 2003/09/09 : CIA-RDP96-00787R000200090021-0 1W Moe QUANTUM PHYSICS AND PARAPSYCHOLOGY The 23rd Annual International Conference of the Parapsychology Foundation, Inc. Hotel La Reserve, Geneva, Switzerland August 26-27, 1974 An interpretative conference report containing some connnents about prospects in parapsychological research. (cia.gov)
The putative relation between quantum physics and para- psychology arises because the apparent non-common sense features accepted in quantum physics may be analogous to the non-common sense features observed in parapsychological phenomena. (cia.gov)
Dr. Hermann Uys holds a CSIR Research Chair in Quantum, Optical and Atomic Physics seated at Stellenbosch University. (sun.ac.za)
He is currently a PhD student studying theoretical physics with a focus on quantum measurement theory. (sun.ac.za)
In the Casimir physics, this response is described either by the dissipative Drude model resulting in contradictions with the measurement data or by the experimentally consistent but dissipationless plasma model. (mdpi.com)
Professor Jared Cole is a member of the Physics discipline of the School of Science and leader of the Theoretical Chemical and Quantum Physics research group. (edu.au)
He is a theoretical physicist, specialising in quantum theory and its application in electronics, computing and condensed-matter physics. (edu.au)
His current research interests include quantum circuit theory, spin physics, decoherence, measurement and entanglement theory, quantum information and computing. (edu.au)
In the philosophy of spacetime physics, Butterfield has argued for a resolution of Einstein's 1913 hole argument that preserves spacetime substantivalism by utilizing David Lewis 's theory of modal counterparts. (wikipedia.org)
There are 1.3 [tons] of copper and 14,000 screws in our machine, as well as a great deal of physics knowledge and engineering know-how," says quantum physicist Andreas Wallraff, also from ETH Zurich. (sciencealert.com)
Our work demonstrates that non-locality is a viable new resource in quantum information technology realized with superconducting circuits with potential applications in quantum communication, quantum computing , and fundamental physics," write the researchers in their published paper. (sciencealert.com)

Closing all these loopholes by making sure the assumptions cannot be violated in the experiment is challenging: Quantum entanglement is fragile and noise is omnipresent. (blogspot.com)
Experiments since have shown that quantum entanglement is indeed possible and that two entangled particles can be connected over a distance. (sciencealert.com)
Researchers used microwave photons to create the entanglement, and more than a million measurements were evaluated to show the violation of Bell's inequality. (sciencealert.com)
The essential quantum resource behind the envisioned quantum light spectroscopy is the photons' time-frequency entanglement. (lu.se)

Recent publications attempt to deal with this issue by including the apparatus into the formalism, connecting AQFT with measurement theory, but other options have been suggested. (pitt.edu)
As a consequence no prediction of standard quantum formalism for microsystems is changed in any appreciable way. (informationphilosopher.com)

Mar. 23, 2022 Two teams of physicists have designed the first programmable quantum sensor, and tested it in the laboratory. (sciencedaily.com)

Oct. 2, 2019 The quantum superposition principle has been tested on a scale as never before in a new study. (sciencedaily.com)

The usual quantum mechanical description of measurements, unitary kicks, and other local operations has the potential to produce pathological causality violations in the relativistic setting of quantum field theory (QFT). (pirsa.org)
This may seem limiting and artificial in the operator language of algebraic quantum field theory (AQFT), but is essential for a truly relativistic theory. (pitt.edu)
He has also investigated the problems of localizability in relativistic quantum theories, in collaboration with Gordon Fleming. (wikipedia.org)

Open quantum systems and study of decoherence are important for our fundamental understanding of quantum physical phenomena. (jyu.fi)
Quantum sensing and using induced decoherence as a probe of dissipative environments. (edu.au)

Loveridge, Dridi and Raussendorf apply this unification to measurement-based quantum computation [14], revealing links between computation, contextuality and the. (tudelft.nl)

The cytometer uses a photon-number resolving detector (or a detector arrangement capable of resolving photon numbers, such as Hanbury-Brown Twiss arrangement), accumulating times of arrival and photon number statistics and using first principles of quantum optics that provide a number of participating emitters. (nist.gov)
The second-order correlation functions relate to concentrations via laws of quantum optics, this dependence does not require the prior knowledge of transmittance losses and detection inefficiencies, even with an unknown optical background present. (nist.gov)
He received his MSc from the University of Pretoria in South Africa and a PhD in quantum optics from the University of Arizona, USA. (sun.ac.za)
Quantum optics describes how individual quanta of light, the photons, interact with atoms, molecules and larger pieces of matter. (lu.se)
Our research areas among other things include quantum information, quantum computing, quantum optics, experiments using slow light (a few km/s), ultra-stable lasers and medical imaging. (lu.se)
In this project you will combine lasers, optics and feedback/control design to make a stabilization setup that will help us improve our quantum computer readout. (lu.se)
Quantum control of HHG is a vast subject with applications from the microscopic atomic scale, where electron correlation and molecular dynamics, to the macroscopic scale of optics. (lu.se)

Quantum stochastic differential equations and quantum jumps. (bilkent.edu.tr)
GianCarlo Ghirardi is the intellectual leader of a group of physicists who want to modify the linear Schrödinger equation, adding nonlinear stochastic terms to cause the "collapse" of the wave function during a quantum measurement . (informationphilosopher.com)
In the philosophy of quantum theory, Butterfield has proposed several clarifications of the notions of locality operative in algebraic quantum field theories (especially 'stochastic Einstein locality'), and has investigated which of these clarified versions of locality hold in those theories. (wikipedia.org)

A fundamental feature of quantum theory is that the predictions it makes are probabilistic. (wikipedia.org)
In recent years, Butterfield has argued for a reconciliation of the idea of emergence - the idea that novel structures, not described by "fundamental" theories, appear at a certain level of complexity - with the possibility of inter-theoretic reduction. (wikipedia.org)
A natural and fundamental question is then whether there are yet-to-be discovered optical QKD protocols (without quantum repeaters) that could circumvent this rate-distance tradeoff. (nature.com)
Primitive Ontology and the Structure of Fundamental Physical Theories. (philpapers.org)

E=m*c^2 and E=hf , Einsteins formula nad Planks formula for the energy of a photon give m=hf/c^2 so photons have an equivalent mass and it is quantum mechanical duality , light is both mass and energy. (thenakedscientists.com)
this is quantum mechanical duality where light is both a particle and a wave. (thenakedscientists.com)
According to the authors, it is possible with presently available technology to perform a Bell-test with such distant sources, thus pushing back the limit on conspiracies that could allow hidden variable theories to deliver quantum mechanical correlations. (blogspot.com)
The operational definition of a weak value for a quantum mechanical system involves the limit of the weak measurement strength tending to zero. (lu.se)

Recent attosecond experiments, based on laser-assisted photoionization (LAP), has allowed for direct measurements of photoionization delays, where diagrammatic many-body perturbation theory has been used to understand electron-electron correlation effects in photoionization. (lu.se)

My main research interests are quantum measurements, quantum control, and quantum thermodynamics. (lu.se)

The use of quantum circuits for applications in quantum computing and quantum metrology. (edu.au)

Microwave photons are one of the main interaction media in solid-state quantum devices such as superconducting and semiconducting qubits. (lu.se)

Experimental projects would typically involve construction and then testing of equipment or devices for new experiments in actual measurement situations. (lu.se)
For the intermediate S2 and S3 structures there is also which ligands are water and which are hydroxides, agree, along nearly complete agreement between quantum chemical modeling with which manganese are Mn(III) and which are Mn(IV) at that and experiments. (lu.se)

Under the resulting two-times inference, such states not only become accessible, but further reveal novel and intriguing properties of quantum reality. (nature.com)

In standard quantum theory, where only measurement makes a value valid, such "unmeasured values" seem to be meaningless. (nature.com)
Quantum projection noise and standard quantum limit. (bilkent.edu.tr)
Obviously these modifications must leave practically unaltered all standard quantum predictions about microsystems. (informationphilosopher.com)

Light produced by a system of few optically active biomarkers (fluorescent molecules, quantum dots) exhibits quantum behavior. (nist.gov)
For the electronic part of the system, we focus on using quantum dots that enable to build photodetectors in the microwave domain and strong coherent coupling between electric charge and microwave photons in the electrical circuits. (lu.se)

In July 2017 Nancy joined the ion trap group as a PhD student and her work will focus on quantum weak measurements. (sun.ac.za)

Here, using a combination of angle-resolved photoemission spectroscopy and quantum oscillation measurements, together with density functional theory calculations, we identify the square-net compound EuGa4 as a magnetic Weyl nodal ring semimetal, in which the line nodes form closed rings near the Fermi level. (bvsalud.org)
In contrast, our previous density functional theory disagreement for the fast-exchanging substrate. (lu.se)
In another EXAFS quantum chemical studies using density functional theory (DFT) study by Dau and coworkers (20), only two short Mn-Mn dis- have played a major role for obtaining a mechanistic under- tances of 2.7 Å were suggested. (lu.se)

However, the authors postulate such an interpretation for the specific q-probabilities pertaining to the indications of the pointer of the measurement device. (sciencedaily.com)
Feyerabend P. K. On the Interpretation of Scientific Theories. (gtmarket.ru)
Feyerabend P. K. Bohr's Interpretation of the Quantum Theory. (gtmarket.ru)
Our studies lay the foundation for the future development of the technique and interpretation of ARPES measurements of field-tunable quantum phases. (bvsalud.org)

te Quantum Yield Measurements as well as precise measurements of the spectral dependence of reflection and/or absorption of powder samples, require an integrating sphere. (edinst.com)
The integrating sphere for powder measurements (part number: 1-M-3) has been designed to meet the specific requirements for the measurements of spectral reflection, absorption and quantum yield of powders. (edinst.com)
It should be noted that precise spectral correction is essential for the quantum yield calculation. (edinst.com)
Reflectance measurements are made by using Synchronous spectral scans, with both excitation and emission monochromators stepping through the pre-set spectral range. (edinst.com)
Two measurements are required: A spectral scan of the diffuse reflected light from the sample under investigation, and a second measurements under identical conditions with a reference scatterer in place of the sample. (edinst.com)
The idea lies in simultaneously high temporal and spectral resolution achievable in a single measurement, as no time-frequency uncertainty applies to the time-frequency entangled pairs. (lu.se)

We construct and experimentally implement a quantum optical probing measurement where measurements on the probes, i.e., the photons' polarization states, are used to extract information on the systems, i.e., the frequency spectra of the same photons. (jyu.fi)
Quantum coherence in low-temperature electronics and spin systems. (edu.au)
More recent examples are Vaidman's criterion for the past of a quantum particle [8] and Aharonov's and his collaborators' focus on aspects of QM correlations in composite systems [9,10]. (lu.se)
We focus on studies of light interacting with nanoscale systems, in both experiment and theory. (lu.se)
Research in this area sets focus on the theory of quantum-optically confined systems of ultra-cold atoms and molecules and related nanostructures. (lu.se)
We work on novel quantum systems at the crossover between the few- and many-body limit, studying precursors of phase transitions and hitherto unknown states of quantum matter, such as self-bound bosonic quantum droplets or dipolar supersolidity. (lu.se)
Attoscience is the study of electron dynamics in quantum systems, such as atoms, molecules and solids, on a time scale down to a few attoseconds (1 as = 10^-18 s). (lu.se)
Can we interest you in a thesis project in artificial neural networks, systems biology, bionanophysics or quantum computing? (lu.se)

light probably attracts mass and is attracted to it and it would be a modification of general relativity and it would be quantum gravity. (thenakedscientists.com)
These address the role of topos theory in understanding quantum theory (in particular the Kochen-Specker theorem ), and the status of time in the various quantum gravity research programmes. (wikipedia.org)

The procedure for finding a probability involves combining a quantum state, which mathematically describes a quantum system, with a mathematical representation of the measurement to be performed on that system. (wikipedia.org)
The mathematical tools for making predictions about what measurement outcomes may occur, and how quantum states can change, were developed during the 20th century and make use of linear algebra and functional analysis. (wikipedia.org)
The computer scientist then reduces computing to a logical machine, which the physicist reduces to atoms and molecules, which a mathematician reduces to a mathematical theory (about Hilbert Spaces), which reduces to the idea of functions, which reduces to an ordered set of numbers. (uncommondescent.com)
For example, Wigner showed how 'measurement' could be analyzed in terms of conscious observation, and it is possible to make this latter notion precise in terms of modern mathematical theories of consciousness such as the integrated information theory. (cam.ac.uk)

a random measurement on two entangled qubit (quantum bit) particles at the same time. (sciencealert.com)

The uncertainty principle implies that, whatever the quantum state, the range of predictions for the electron's position and the range of predictions for its momentum cannot both be narrow. (wikipedia.org)
For example: the parallel universes must have all come into being simultaneously "at the beginning" in order for quantum uncertainty to exist, because there was no observer present at the Big Bang, thus no way for the Wave Function to collapse and produce one universe out of all the bubbles of possibility (p.174). (incunabula.org)
4. formulate expressions for a measurement on a quantum particle and explain central concepts as probability, outcome, expectation value and uncertainty. (lu.se)

We enhance an optical flow cytometer with a photon- number statistics measurement. (nist.gov)
Measurement of photon number statistics can unambiguously resolve the number of emitters in the system and it is resilient to loss. (nist.gov)
We develop detectors and spectroscopy tapping into the quantum properties of the entangled photons and single photon detectors with high quantum efficiency. (lu.se)

For example, a quantum particle like an electron can be described by a quantum state that associates to each point in space a complex number called a probability amplitude. (wikipedia.org)
The same quantum state can also be used to make a prediction of how the electron will be moving, if an experiment is performed to measure its momentum instead of its position. (wikipedia.org)
If an electron can disappear in one universe and appear in another (as suggested by the Everett/Wheeler material), a process called "quantum tunneling", then perhaps information can undergo a similar tunneling effect. (incunabula.org)

This outcome is then corroborated by adding weak measurements and the Aharonov-Bohm effect. (nature.com)
Weak measurements. (bilkent.edu.tr)

We examined these effects in three prototypical quantum materials, i.e., a topological insulator (Bi2Se3), an iron-based superconductor (LiFeAs), and a cuprate superconductor (Pb-Bi2Sr2CuO6+x), and demonstrate the feasibility of ARPES measurements in the presence of a controllable magnetic field. (bvsalud.org)

Complexity theory formalizes the notion of proof in a way that emphasizes the role played by the verification procedure. (acm.org)

I conclude by considering an MCI -like theory that avoids the dilemma by combining the integrated information theory of consciousness with the continuous spontaneous localization theory of collapse. (cam.ac.uk)

I then present measurement theory in AQFT, modelling the apparatus as a quantum field with coupling to the measured system restricted to a region of spacetime. (pitt.edu)
Bell had criticized the work of John von Neumann , who could not locate the boundary between the quantum system and the classical measuring apparatus. (informationphilosopher.com)

The quantity Quantum Yield, η, is defined by the sum of all emitted photons, divided by the sum of all absorbed photons. (edinst.com)
Note that this method is based on the direct measurement of the number of emitted and absorbed photons, it is often referred to as absolute method for the determination of the Emission Quantum Yield. (edinst.com)
Our motivation for this is to create and study hybridized quantum states between electrons and photons. (lu.se)
We study experimentally and theoretically microwave photons interacting with electrons in semiconductor nanostructures in so-called circuit quantum electrodynamics (cQED) setup. (lu.se)

For local observables in QFT it is an open question whether the projection postulate, or more specifically the associated ideal measurement operation, is consistent with causality, and hence whether it is physically realisable in principle. (pirsa.org)
Requiring causality on measurements in quantum field theory seems to impose strong conditions on a self-adjoint operator to be really measurable. (pitt.edu)
In this essay, I discuss the causality conditions on self-adjoint operators both in the language of AQFT and in the language of quantum information theory. (pitt.edu)
Finally, I attempt to formulate the causality conditions on measurements in the Feynman path integral approach, using the concept of decoherent histories. (pitt.edu)

The eigenvectors of a von Neumann observable form an orthonormal basis for the Hilbert space, and each possible outcome of that measurement corresponds to one of the vectors comprising the basis. (wikipedia.org)
In any natural science, measurements are the essential link between theory and observable reality. (jyu.fi)

With this we find that, under certain assumptions - such as there being a continuum spacetime - ideal measurements of smeared fields are acausal, despite prior heuristic arguments to the contrary. (pirsa.org)
It allows to describe properties of individual runs, and provides a justification to all properties usually attributed to ideal measurements. (sciencedaily.com)

Elsewhere (p.204), Wolf speculates that a future "highly developed…electronic form of biofeedback" will allow us to observe quantum effects in the electrons of our own bodies, making the enhanced consciousness and the body itself a "time machine" (which is what he calls a device for travel between universes). (incunabula.org)

Researchers have discovered a new generic production mechanism of gravitational waves generated by a phenomenon known as oscillons, which can originate in many cosmological theories from the fragmentation into solitonic "lumps" of the inflaton field that drove the early Universe's rapid expansion, reports a new study published in Physical Review Letters . (sciencedaily.com)

The calculations were performed on a D-Wave Advantage quantum annealer. (lu.se)

Professor Hoi-Kwong Lo's PhD student, (Mike) Wenyuan Wang, won the Best Student Paper Award at the QCrypt conference (August 27-31, 2018) - the largest scientific conference in quantum cryptography. (utoronto.ca)

For each measurement that can be defined, the probability distribution over the outcomes of that measurement can be computed from the density operator. (wikipedia.org)

Wenyuan's paper was titled: 'Enabling a Scalable High-Rate Measurement-Device-Independent Quantum Key Distribution Network: theory and experiment. (utoronto.ca)
Not only does this experiment run the Bell test at longer distances than previously attempted, but it also runs it using superconducting circuits, which are expected to play a significant role in the development of quantum computers . (sciencealert.com)

Assigning a pure state to a quantum system implies certainty about the outcome of some measurement on that system (i.e. (wikipedia.org)
Yet when we perform a single measurement, we find a well-defined outcome. (sciencedaily.com)

Since 1984, various optical quantum key distribution (QKD) protocols have been proposed and examined. (nature.com)
Our result has major implications for understanding the secret key agreement capacity of optical channels-a long-standing open problem in optical quantum information theory-and strongly suggests a real need for quantum repeaters to perform QKD at high rates over long distances. (nature.com)
The natural question that thus arises is whether there are yet-to-be-discovered optical QKD protocols that could circumvent the exponential rate-distance tradeoff of BB84 and transmit at high rates over long distances without the need for quantum repeaters. (nature.com)
Artist view of a quantum optical trap with ultra-cold fermions. (lu.se)
Therefore, there is an ongoing effort to use an optical micro-cavity to enhance the fluorescence from them by using quantum optic effects to reduce their spontaneous lifetime. (lu.se)
By performing optical measurements, the fraction of melting base pairs as a function of temperature can be extracted. (lu.se)

To remove all potential loopholes from a Bell test, measurements be taken in less time than it takes for light to travel from one end to another - which proves no information has been exchanged between them. (sciencealert.com)

The experimental data will be compared with theoretical modelling carried out at the division electromagnetic field theory. (lu.se)

Here, we develop a novel spin representation for lattice protein folding tailored for quantum annealing. (lu.se)

We thereby place on a firm foundation the need for quantum repeaters for high-rate QKD over long distances with no trusted relays. (nature.com)

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