Detecting nonlocality in many-body quantum states

@article{Brugus2014DetectingNI,
  title={Detecting nonlocality in many-body quantum states},
  author={Jordi Tura i Brugu{\'e}s and Remigiusz Augusiak and Ana Bel{\'e}n Sainz and Tam{\'a}s V{\'e}rtesi and Maciej Lewenstein and Antonio Ac{\'i}n},
  journal={Science},
  year={2014},
  volume={344},
  pages={1256 - 1258}
}
Testing nonlocality for many particles Distant parts of a quantum-mechanical system can be correlated in ways that cannot be described classically—a concept known as nonlocality. Tura et al. propose a simple test for nonlocality in systems with multiple particles. The test involves quantities that should readily be measurable in, for example, cold atom experiments. This is an improvement over currently available tests, which are difficult to implement experimentally. Science, this issue p. 1256… 

Detection of nonlocality with two-body correlation functions

Nonlocality detection in multipartite quantum systems is of great interest. The most popular tool to detect nonlocality in quantum systems are Bell inequalities. Most of the provided constructions of

Bell correlation depth in many-body systems

We address the question of assessing the number of particles sharing genuinely nonlocal correlations in a multipartite system. While the interest in multipartite nonlocality has grown in recent

Energy as a Detector of Nonlocality of Many-Body Spin Systems

We present a method to show that low-energy states of quantum many-body interacting systems in one spatial dimension are nonlocal. We assign a Bell inequality to the Hamiltonian of the system in a

Translationally invariant multipartite Bell inequalities involving only two-body correlators

Bell inequalities are natural tools that allow one to certify the presence of nonlocality in quantum systems. The known constructions of multipartite Bell inequalities contain, however, correlation

Entanglement and Nonlocality in Infinite 1D Systems.

TLDR
This work provides a simple characterization of the set of local states of multiseparable TI spin chains and construct a family of linear witnesses which can detect entanglement in infinite TI states from the nearest-neighbor reduced density matrix and proves that theset of classical TI boxes forms a polytope and devise a general procedure to generate all Bell inequalities which characterize it.

Bell Non-Locality in Many-Body Quantum Systems with Exponential Decay of Correlations

TLDR
Using clustering theorems, it is able to show that a large family of quantum many-body systems behave almost locally, violating Bell-inequalities (if so) only by a non-significant amount.

Entanglement and Nonlocality of 1D Macroscopic Systems

We consider the problem of certifying entanglement and nonlocality in one-dimensional macroscopic systems when just averaged near-neighbor correlators are available. We map this question to the

Quantum correlations in spin chains

The growth in the demand for precisely crafted many-body systems of spin-$1/2$ particles/qubits is due to their top-notch versatility in application-oriented quantum-enhanced protocols and the

Entanglement, nonlocality and multi-particle quantum correlations

This paper contributes to the proceedings of the Latin-American School of Physics (ELAF-2017) on Quantum Correlations, and is a brief review of quantum entanglement and nonlocality. In such a brief
...

References

SHOWING 1-10 OF 36 REFERENCES

Quantum non-demolition detection of strongly correlated systems

Preparation, manipulation and detection of strongly correlated states of quantum many-body systems are among the most important goals and challenges of modern physics. Ultracold atoms offer an

Bell nonlocality

Nonlocality was discovered by John Bell in 1964, in the context of the debates about quantum theory, but is a phenomenon that can be studied in its own right. Its observation proves that measurements

N-particle nonclassicality without N-particle correlations

Most of known multipartite Bell inequalities involve correlation functions for all subsystems. They are useless for entangled states without such correlations. We give a method of derivation of

Many-particle entanglement with Bose–Einstein condensates

TLDR
This work proposes a method to achieve substantial entanglement of a large number of atoms in a Bose–Einstein condensate, which is then allowed to evolve freely and should be realizable with present technology.

Nonlocal multipartite correlations from local marginal probabilities

Understanding what can be inferred about a multiparticle quantum system given only the knowledge of its subparts is a highly nontrivial task. Clearly, if a global system does not contain an

Entanglement in a simple quantum phase transition

What entanglement is present in naturally occurring physical systems at thermal equilibrium? Most such systems are intractable and it is desirable to study simple but realistic systems that can be

Scaling of entanglement close to a quantum phase transition

TLDR
It is demonstrated, for a class of one-dimensional magnetic systems, that entanglement shows scaling behaviour in the vicinity of the transition point, which connects the theory of critical phenomena with quantum information by exploring the entangling resources of a system close to its quantum critical point.

Testing the structure of multipartite entanglement with Bell inequalities.

TLDR
The rich structure of multipartite entanglement can be tested following a device-independent approach and 'subcorrelation Bell inequalities' are devised, which give insight into the nonlocality of W states.

Quantum interface between light and atomic ensembles

During the past decade the interaction of light with multiatom ensembles has attracted much attention as a basic building block for quantum information processing and quantum state engineering. The

Criticality, the area law, and the computational power of projected entangled pair states.

TLDR
It is proved that coherent versions of thermal states of any local 2D classical spin model correspond to PEPS, which are in turn ground states of local2D quantum Hamiltonians, and this correspondence maps thermal onto quantum fluctuations.