The von Neumann Entropy for Mixed States

Anaya-Contreras, Jorge A.; Moya‐Cessa, H.; Zúñiga-Segundo, Arturo

doi:10.3390/e21010049

Cited by 16 publications

(7 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By having the density operator, one can calculate all quantum coherence properties or entanglement criteria. Although there are many references which addressed two-qubit entropy measures (Anaya-Contreras et al 2019;Khordad and Servatkhah 2017;Friis et al 2017;Rehman and Shin 2019), but, very recently, it has been theoretically developed and experimentally demonstrated a new method, resourceand computationally efficient, for quantum state tomography in Fock basis via Wigner function reconstruction and semidefinite programming (Nehra et al 2020). They have shown that obtained density operator from this method is robust against the noise of measurement and relies on no approximate state displacements, and requires all physical properties.…”

Section: Introductionmentioning

confidence: 99%

Measurement of entropy and quantum coherence properties of two type-I entangled photonic qubits

2021

View full text Add to dashboard Cite

Using the type-I SPDC process in BBO nonlinear crystal, we generate a polarization-entangled state near to the maximally-entangled Bell-state with high-visibility (high-brightness) 98.50 ± 1.33% (87.71 ± 4.45%) for HV (DA) basis. We calculate the CHSH version of the Bell inequality, as a nonlocal realism test, and find a strong violation from the classical physics or any hidden variable theory, S = 2.71 ± 0.10. Via measuring the coincidence count rate in the SPDC process, we obtain the quantum efficiency of single-photon detectors around (25.5 ± 3.4)%, which is in good agreement to their manufacturer company. As expected, we verify the linear dependency of the CC rate vs. pump power of input CW-laser, which may yield to find the effective second-order susceptibility crystal. Using the theory of the measurement of qubits, includes a tomographic reconstruction of quantum states due to the linear set of 16 polarization-measurement, together with a maximum-likelihood-technique, which is based on the numerical optimization, we calculate the physical non-negative definite density matrices, which implies on the non-separability and entanglement of prepared state. By having the maximum likelihood density operator, we calculate precisely the entanglement measures such as Concurrence, entanglement of formation, tangle, logarithmic negativity, and different entanglement entropies such as linear entropy, Von-Neumann entropy, and Renyi 2-entropy. Finally, this high-brightness and low-rate entangled photons source can be used for short-range quantum measurements in the Lab.

show abstract

Section: Introductionmentioning

confidence: 99%

Measurement of entropy and quantum coherence properties of two type-I entangled photonic qubits

2021

View full text Add to dashboard Cite

show abstract

“…We note that Anaya-Contreras et al have proposed a method to calculate the von Neumann entropy of a larger system from the entropy of a subsystem that is initially in a mixed state. 181…”

Section: Circuit For Schrödinger's Cat States Von Neumann Entropy And...mentioning

confidence: 99%

Shannon and von Neumann entropies of multi-qubit Schrödinger's cat states

Jansen

Loucks

Gilbert

et al. 2022

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…In general, the maximum value of S N is ln N, where N is the number of states of one qubit. The system will be maximally entangled when all the probability amplitudes c m , for m = 1, 2, ...N, reach the same value, c m = 1/N [32].…”

Section: Maximally Entangled States and Entanglement Entropymentioning

confidence: 99%

Photon Enhanced Interaction and Entanglement in Semiconductor Position-Based Qubits

Giounanlis

Blokhina

Leipold³

et al. 2019

Applied Sciences

View full text Add to dashboard Cite

CMOS technologies facilitate the possibility of implementing quantum logic in silicon. In this work, we discuss a minimalistic modelling of entangled photon communication in semiconductor qubits. We demonstrate that electrostatic actuation is sufficient to construct and control desired potential energy profiles along a Si quantum dot (QD) structure allowing the formation of position-based qubits. We further discuss a basic mathematical formalism to define the position-based qubits and their evolution under the presence of external driving fields. Then, based on Jaynes-Cummings-Hubbard formalism, we expand the model to include the description of the position-based qubits involving four energy states coupled with a cavity. We proceed with showing an anti-correlation between the various quantum states. Moreover, we simulate an example of a quantum trajectory as a result of transitions between the quantum states and we plot the emitted/absorbed photos in the system with time. Lastly, we examine the system of two coupled position-based qubits via a waveguide. We demonstrate a mechanism to achieve a dynamic interchange of information between these qubits over larger distances, exploiting both an electrostatic actuation/control of qubits and their photon communication. We define the entanglement entropy between two qubits and we find that their quantum states are in principle entangled.

show abstract

The von Neumann Entropy for Mixed States

Cited by 16 publications

References 24 publications

Measurement of entropy and quantum coherence properties of two type-I entangled photonic qubits

Measurement of entropy and quantum coherence properties of two type-I entangled photonic qubits

Shannon and von Neumann entropies of multi-qubit Schrödinger's cat states

Photon Enhanced Interaction and Entanglement in Semiconductor Position-Based Qubits

Contact Info

Product

Resources

About