Albert Einstein and his colleagues Boris Podolsky and Nathan Rosen ( known collectively as EPR ) designed a thought experiment intended to reveal what they believed to be inadequacies of quantum mechanics.

EPR tried to set up a paradox to question the range of true application of Quantum Mechanics: Quantum theory predicts that both values cannot be known for a particle, and yet the EPR thought experiment purports to show that they must all have determinate values.

In 1964, John Bell showed that the predictions of quantum mechanics in the EPR thought experiment are significantly different from the predictions of a particular class of hidden variable theories ( the local hidden variable theories ).

In the EPR paper ( 1935 ) the authors realised that quantum mechanics was inconsistent with their assumptions, but Einstein nevertheless thought that quantum mechanics might simply be augmented by hidden variables ( i. e. variables which were, at that point, still obscure to him ), without any other change, to achieve an acceptable theory.

Nevertheless, consider the EPR thought experiment, and suppose quantum states could be cloned.

In this study, they formulated the EPR paradox ( Einstein, Podolsky, Rosen Paradox ), a thought experiment that attempted to show that quantum mechanical theory was incomplete.

Schrödinger intended his thought experiment as a discussion of the EPR article — named after its authors Einstein, Podolsky, and Rosen — in 1935.

Consider the EPR thought experiment, and suppose quantum states could be cloned.

1964: John Stewart Bell published his inequalities showing that the predictions of quantum mechanics in the EPR thought experiment are significantly different from the predictions of a particular class of hidden variable theories ( the local hidden variable theories ).

This failure of the classical view was one of the conclusions of the EPR thought experiment in which two remotely located observers, now commonly referred to as Alice and Bob, perform independent measurements of spin on a pair of electrons, prepared at a source in a special state called a spin singlet state.

This thought experiment, which came to be known as the EPR paradox, hinges on the principle of locality.

EPR thought experiment

It concerns discussion and experimental determination of whether local hidden variables are required for, or even compatible with, the representation of experimental results ; with particular relevance to the EPR thought experiment and the CHSH inequality.

This spin up / down formulation was proposed by David Bohm, who conceived of spin as an observable in a version of thought experiments formulated in the 1935 EPR paradox.

Two of the most famous of these are the EPR paradox and Schrödinger's cat, both proposed as thought experiments relevant to the discussions of the correct interpretation of quantum mechanics.

Since the source of an EPR spectrum is a change in an electron's spin state, it might be thought that all EPR spectra for a single electron spin would consist of one line.

At the time the EPR article was written, it was known from experiments that the outcome of an experiment sometimes cannot be uniquely predicted.

Therefore, as outlined in the example above, neither the EPR experiment nor any quantum experiment demonstrates that faster-than-light signaling is possible.

* EPR experiment with single photons interactive.

Following the EPR paper, Erwin Schrödinger wrote a letter ( in German ) to Einstein in which he used the word Verschränkung ( translated by himself as entanglement ) " to describe the correlations between two particles that interact and then separate, as in the EPR experiment ".

There are quantum mechanics references as well ; phenomena of non-locality, as in the EPR paradox, make appearances, and the concept of Schrödinger's Cat plays a part in helping Dirk determine Richard's mental state, Richard producing clear and rational arguments for why the experiment proposed in the theory cannot be carried out in reality.

Following the argument in the Einstein – Podolsky – Rosen ( EPR ) paradox paper ( but using the example of spin, as in David Bohm's version of the EPR argument ), Bell considered an experiment in which there are " a pair of spin one-half particles formed somehow in the singlet spin state and moving freely in opposite directions.

In terms of the EPR experiment, in some reference frames measurement of photon A will cause the wave function to collapse, but in other reference frames the measurement of photon B will cause the collapse.

Fredkin takes a radical approach to explaining the EPR paradox and the double-slit experiment in quantum mechanics.

EPR color experiment illustration

Such explanations, which are still encountered in popular expositions of quantum mechanics, are debunked by the EPR paradox, which shows that a " measurement " can be performed on a particle without disturbing it directly, by performing a measurement on a distant entangled particle.

At location A, a Bell measurement of the EPR pair qubit and the qubit to be teleported ( for example, quantum state of a photon ) is performed, yielding two classical bits of information.

* EPR paradox ( quantum mechanics ) ( forms of this have actually been performed )

Though the EPR paper has often been taken as an exact expression of Einstein's views, it was primarily authored by Podolsky, based on discussions at the Institute for Advanced Study with Einstein and Rosen.

Theoretical developments have gone hand in hand with developments in experimental methods, where the use of different forms of spectroscopy, such as infrared spectroscopy, microwave spectroscopy, EPR spectroscopy and NMR spectroscopy, is probably the most important 20th century development.

But explanations of the EPR experiments that are consistent with standard microscopic quantum mechanics require that macroscopic objects, such as cats and notebooks, do not always have unique classical descriptions.

In 1935, with two coworkers, he published a famous paper on a newly-created subject called later the EPR effect ( EPR paradox ).

The Pacific is also home to one of the world's most active spreading centres ( the East Pacific Rise ( EPR )) with spreading rates of up to 13 cm / yr.

* PEG, when labeled with a near-infrared fluorophore, has been used in preclinical work as a vascular agent, lymphatic agent, and general tumor-imaging agent by exploiting the Enhanced permeability and retention effect ( EPR ) of tumors.

* Nathan Rosen, co-author with Albert Einstein and Boris Podolsky of physics paper about the EPR paradox in quantum mechanics

# A measurable property of a physical system whose value can be predicted with certainty is actually an element of reality ( this was the terminology used by EPR ).

It was a conclusion of EPR, using the formal apparatus of quantum theory, that once Alice measured spin in the x direction, Bob's measurement in the x direction was determined with certainty, whereas immediately before Alice's measurement Bob's outcome was only statistically determined.

Another dating method using electron spin resonance ( ESR ) — also known as electron paramagnetic resonance ( EPR ) — is based on the measurement of electron-hole centers accumulated with time in the crystal lattice of CaCO < sub > 3 </ sub > exposed to natural radiations.

The EFG couples with the nuclear electric quadrupole moment of quadrupolar nuclei ( those with spin quantum number greater than one-half ) to generate an effect which can be measured using several spectroscopic methods, such as nuclear magnetic resonance ( NMR ), electron paramagnetic resonance ( EPR, ESR ), nuclear quadrupole resonance ( NQR ), Mössbauer spectroscopy or perturbed angular correlation ( PAC ).

Tires are an example of products subject to extended producer responsibility in many industrialized countries. In the field of waste management, extended producer responsibility ( EPR ) is a strategy designed to promote the integration of environmental costs associated with goods throughout their life cycles into the market price of the products.

An EPR pair is a pair of qubits which jointly are in a Bell state, that is, entangled with each other.

The argument of EPR was in 1957 picked up by David Bohm and Yakir Aharonov in a paper published in Physical Review with the title Discussion of Experimental Proof for the Paradox of Einstein, Rosen, and Podolsky.

Bohr's response to this argument was published, five months later than the original publication of EPR, in the same magazine Physical Review and with exactly the same title as the original.

The leaders in national experience with PWRs, offering reactors for export, are the United States ( which offers the passively-safe AP1000, a Westinghouse design, as well as several smaller, modular, passively-safe PWRs, such as the Babcock and Wilcox MPower, and the NuScale MASLWR ), the Russian Federation ( offering both the VVER-1000 and the VVER-1200 for export ), the Republic of France ( offering the AREVA EPR for export ), and Japan ( offering the Mitsubishi Advanced Pressurized Water Reactor for export ); in addition, both the People's Republic of China and the Republic of Korea are both noted to be rapidly ascending into the front rank of PWR-constructing nations as well, with the Chinese being engaged in a massive program of nuclear power expansion, and the Koreans currently designing and constructing their second generation of indigenous designs.

Dr. Ralf Langen's group showed that SDSL with EPR ( University of Southern California, Los Angeles ) can be used to understand the structure of amyloid fibrils and the structure of membrane bound Parkinson's disease protein alpha-synuclein.