Experimental generation of 6 dB continuous variable entanglement from a nondegenerate optical parametric amplifier

Wang, Yu; Shen, Heng; Jin, Xiaoli; Su, Xiaolong; Xie, Changde; Peng, Kunchi

doi:10.1364/oe.18.006149

Cited by 58 publications

(45 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In our scheme the variance of the excess noise is the quantum correlation variances of the EPR entangled state [21], i.e. ∆ 2 (x 1 +x 2 ) = ∆ 2 (p 1 −p 2 ) = e −2rE /2.…”

Section: Protocol and Principle Of Quantum Logical Operationsmentioning

confidence: 99%

Gates for one-way quantum computation based on Einstein-Podolsky-Rosen entanglement

Hao

Deng

et al. 2014

Phys. Rev. A

Self Cite

View full text Add to dashboard Cite

Single-mode squeezing and Fourier transformation operations are two essential logical gates in continuous-variable quantum computation, which have been experimentally implemented by means of an optical four-mode cluster state. In this paper, we present a simpler and more efficient protocol based on the use of Einstein-Podolsky-Rosen two-mode entangled states to realize the same operations. The theoretical calculations and the experimental results demonstrate that the presented scheme not only decreases the requirement to the resource quantum states at the largest extent but also enhances significantly the squeezing degree and the fidelity of the resultant modes under an identical resource condition. That is because in our system the influence of the excess noises deriving from the imperfect squeezing of the resource states is degraded. The gate operations applying two-mode entanglement can be utilized as a basic element in a future quantum computer involving a large-scale cluster state.

show abstract

“…In our scheme the variance of the excess noise is the quantum correlation variances of the EPR entangled state [21], i.e. ∆ 2 (x 1 +x 2 ) = ∆ 2 (p 1 −p 2 ) = e −2rE /2.…”

Section: Protocol and Principle Of Quantum Logical Operationsmentioning

confidence: 99%

Gates for one-way quantum computation based on Einstein-Podolsky-Rosen entanglement

Hao

Deng

et al. 2014

Phys. Rev. A

Self Cite

View full text Add to dashboard Cite

show abstract

“…The entanglement can further be detected with homodyne detections, by means of the Duan -Simon criterion [6,7]. When the χ 2 -nonlinearity is seeded by coherent states and/or embedded in a high finesse cavity, entanglement in squeezed states can be demonstrated with a huge number of photons -so huge that they can be detected with classical power-meters [8][9][10][11][12][13][14]. This naturally raises the question of whether squeezed states have macroscopic quantum features -a question of deep relevance because so far squeezed states have been combined with conditional detections [15][16][17][18][19][20][21] for exploring quantum effects in many photon states.…”

Section: Introduction -mentioning

confidence: 99%

Two-mode squeezed states as Schrödinger cat-like states

et al. 2015

View full text Add to dashboard Cite

In recent years, there has been an increased interest in the generation of superposition of coherent states with opposite phases, the so-called photonic Schrödinger-cat states. These experiments are very challenging and so far, cats involving small photon numbers only have been implemented. Here, we propose to consider two-mode squeezed states as examples of a Schrödinger-cat-like state. In particular, we are interested in several criteria aiming to identify quantum states that are macroscopic superpositions in a more general sense. We show how these criteria can be extended to continuous variable entangled states. We apply them to various squeezed states, argue that two-mode squeezed vacuum states belong to a class of general Schrödinger-cat states and compare the size of states obtained in several experiments. Our results not only promote two-mode squeezed states for exploring quantum effects at the macroscopic level but also provide direct measures to evaluate their usefulness for quantum metrology. Introduction -The question of what is a macroscopic quantum state has received quite a lot of attention over the last decade [1][2][3][4]. The motivation is not to address a new question -not at all, as it dates back from the early days of quantum theory [5] -but rather comes from the experimental progress, now allowing one to harness large systems while highlighting their quantum nature. Quantum optics experiments reporting on squeezing operations provide a nice example. They are obtained from a χ 2 -nonlinearity and can result in largely entangled states. The entanglement can further be detected with homodyne detections, by means of the Duan -Simon criterion [6,7]. When the χ 2 -nonlinearity is seeded by coherent states and/or embedded in a high finesse cavity, entanglement in squeezed states can be demonstrated with a huge number of photons -so huge that they can be detected with classical power-meters [8][9][10][11][12][13][14]. This naturally raises the question of whether squeezed states have macroscopic quantum features -a question of deep relevance because so far squeezed states have been combined with conditional detections [15][16][17][18][19][20][21] for exploring quantum effects in many photon states.In the literature, there exist different criteria for quantifying the macroscopic quantumness [1,[22][23][24][25][26][27][28][29][30][31][32]. Typically, this includes a definition that assigns to a quantum state a number, which is here called effective size (or simply size). Surprisingly, none of them unambiguously applies to two-mode squeezed states and, at the same time, is able to compare their size to those of other states. These criteria can be grouped into two categories. The first one addresses the question of whether a two component superposition |φ 0 + |φ 1 is macroscopic, i.e., whether |φ 0 and |φ 1 are macroscopically distinct. For example, the proposal of Ref. [27] states that two spin states are macroscopically distinct if they can be distinguished from a small number of their spins -as a dea...

show abstract

“…By using a monolithic PPKTP OPA, a 12.7-dB squeezing was also achieved at 1064 nm [21]. For an * zhangyong@nju.edu.cn NOPA, the degree of entanglement for its signal and idler light beams has recently been shown to be as high as 6 dB [22].…”

Section: Introductionmentioning

confidence: 99%

Quantum limits for cascaded optical parametric amplifiers

2013

View full text Add to dashboard Cite

We demonstrate the enhanced quantum noise reduction of the output field from an optical parametric amplifier (OPA) by employing the cascaded optical parametric amplifiers (COPA), in which the output field of one OPA is the input field of the subsequent one. The output field noise formulas of the cascaded degenerate and nondegenerate OPAs (CDOPA and CNOPA) are obtained. The analytical results show that a CDOPA and a CNOPA can generate squeezing beams and entangled beams with a wider bandwidth under a low pump parameter, respectively. The cavity output efficiency and the intracavity loss are the main factors for improving the degrees of squeezing and entanglement. Our work will provide improved schemes for designing COPAs to efficiently produce high-quality squeezed and entangled states, which have potential applications in quantum-information processing.

show abstract

Experimental generation of 6 dB continuous variable entanglement from a nondegenerate optical parametric amplifier

Cited by 58 publications

References 25 publications

Gates for one-way quantum computation based on Einstein-Podolsky-Rosen entanglement

Gates for one-way quantum computation based on Einstein-Podolsky-Rosen entanglement

Two-mode squeezed states as Schrödinger cat-like states

Quantum limits for cascaded optical parametric amplifiers

Contact Info

Product

Resources

About