# Estimating entanglement of unknown states

@article{Cavalcanti2006EstimatingEO, title={Estimating entanglement of unknown states}, author={Daniel Cavalcanti and Marcelo O. Terra Cunha}, journal={Applied Physics Letters}, year={2006}, volume={89}, pages={084102} }

The experimental determination of entanglement is a major goal in the quantum information field. In general, the knowledge of the state is required in order to quantify its entanglement. Here we express a lower bound to the robustness of entanglement of a state based only on the measurement of the energy observable and on the calculation of a separability energy. This allows the estimation of entanglement dismissing the knowledge of the state in question.

## 16 Citations

Single-experiment-detectable multipartite entanglement witness for ensemble quantum computing

- Physics, Computer Science
- 2007

Individual single-qubit measurements are performed simultaneously; hence complete detection of entanglement is performed in a single-run experiment, and the scheme is superior to the generally usedEntanglement witnesses that require a number of experiments and preparation of copies of quantum state for detection of Entanglement.

Quantitative entanglement witnesses

- Physics
- 2006

All these tests—based on the very same data—give rise to quantitative estimates in terms of entanglement measures, and if a test is strongly violated, one can also infer that the state was quantitatively very much entangled, in the bipartite and multipartite setting.

Geometrically induced singular behavior of entanglement

- Physics
- 2008

We show that the geometry of the set of quantum states plays a crucial role in the behavior of entanglement in different physical systems. More specifically, it is shown that singular points at the…

Quantifying necessary quantum resources for nonlocality

- PhysicsPhysical Review Research
- 2022

Nonlocality is one of the most important resources for quantum information protocols. The observation of nonlocal correlations in a Bell experiment is the result of appropriately chosen measurements…

Entanglement detection and distillation for arbitrary bipartite systems

- MathematicsQuantum Inf. Process.
- 2013

An inequality for detecting entanglement and distillability of arbitrary dimensional bipartite systems is presented and it is shown that this inequality provides a necessary and sufficient condition for distillable states.

Entanglement Theory and the Quantum Simulation of Many-Body Physics

- Physics
- 2008

In this thesis we present new results relevant to two important problems in quantum information science: the development of a theory of entanglement and the exploration of the use of controlled…

Modeling the decay of entanglement for electron spin qubits in quantum dots

- PhysicsJournal of physics. Condensed matter : an Institute of Physics journal
- 2009

We investigate the time evolution of entanglement under various models of decoherence: a general heuristic model based on local relaxation and dephasing times, and two microscopic models describing…

Automated machine learning can classify bound entangled states with tomograms

- Computer ScienceQuantum Inf. Process.
- 2021

An Automated Machine Learning approach is presented to classify random states of two qutrits as separable or entangled using enough data to perform a quantum state tomography, without any direct measurement of its entanglement.

Machine-Learning-Assisted Many-Body Entanglement Measurement.

- PhysicsPhysical review letters
- 2018

This work proposes a machine-learning-assisted scheme to measure the entanglement between arbitrary subsystems of size N A and N B, with O(N_{A}+N_{B}) measurements, and without any prior knowledge of the state.

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