Scientists are progressively seeking to find more about quantum entanglement, which happens when two or more systems are created or communicate in such a way that the quantum states of some can not be explained separately of the quantum states of the others. The problem is that light produced by crystal-based OPOs can not engage with other systems of interest in the context of quantum information, such as cold atoms, chips or ions, because its wavelength is not the very same as those of the systems in question. We, therefore, produced the very first OPO based on rubidium atoms, in which two beams were intensely quantum-correlated, and acquired a source that could connect with other systems with the possible to serve as quantum memory, such as cold atoms,” Florez stated.
These possible applications, this kind of light source could likewise be utilized in metrology. Prior to his group performed this research study, other groups had tried to make OPOs with atoms however stopped working to demonstrate quantum connections in the light beams produced.
” This light was an optical parametric oscillator, or OPO, which is typically comprised of a non-linear optical action crystal between 2 mirrors forming an optical cavity. When an intense green beam shines on the device, the crystal-mirror characteristics produce 2 beams with quantum correlations,” stated physicist Hans Marin Florez, last author of the article.
The optical parametric oscillator (OPO) used in the research study. Credit: Alvaro Montaña Guerrero.
The problem is that light given off by crystal-based OPOs can not engage with other systems of interest in the context of quantum information, such as cold atoms, chips or ions, considering that its wavelength is not the like those of the systems in concern. “Our group displayed in previous work that atoms themselves might be used as a medium rather of a crystal. We, therefore, produced the very first OPO based on rubidium atoms, in which two beams were intensely quantum-correlated, and acquired a source that might communicate with other systems with the potential to work as quantum memory, such as cold atoms,” Florez stated.
In addition to the intensity, the beams stages, which have to do with lightwave synchronization, likewise required to show quantum connections. “We duplicated the exact same experiment but included new detection actions that enabled us to determine the quantum connections in the amplitudes and phases of the fields created. Rather of two nearby bands of the spectrum being knotted, what we had in fact produced was a system consisting of 4 entangled spectral bands.”.
In this case, the amplitudes and phases of the waves were entangled. These possible applications, this kind of light source might also be utilized in metrology. “Quantum correlations of strength outcome in a considerable reduction of strength changes, which can enhance the sensitivity of optical sensors,” Florez said.
Enhancing the level of sensitivity of atomic magnetometers used to determine the alpha waves emitted by the human brain is one of the potential applications, he added.
The article likewise notes an extra advantage of rubidium OPOs over crystal OPOs. “Crystal OPOs have to have mirrors that keep the light inside the cavity for longer, so that the interaction produces quantum correlated beams, whereas the usage of an atomic medium in which the 2 beams are produced more effectively than with crystals avoids the need for mirrors to lock up the light for such a long period of time,” Florez said.
Prior to his group conducted this study, other groups had attempted to make OPOs with atoms but stopped working to show quantum correlations in the light beams produced. “We discovered that the temperature of the atoms is key to observation of quantum connections.
Reference: “Continuous Variable Entanglement in an Optical Parametric Oscillator Based on a Nondegenerate Four Wave Mixing Process in Hot Alkali Atoms” by A. Montaña Guerrero, R. L. Rincón Celis, P. Nussenzveig, M. Martinelli, A. M. Marino and H. M. Florez, 11 October 2022, Physical Review Letters.DOI: 10.1103/ PhysRevLett.129.163601.
The research study was supported by FAPESP through a Thematic Project coordinated by IF-USP Professor Marcelo Martinelli, one postdoctoral scholarship given to Florez, and 2 PhD scholarships– one approved to the posts first author Álvaro Montaña Gerreiro and the other to Raul Leonardo Rincon Celis.
Scientists using an optical parametric oscillator source of light was successful in producing 2 knotted light beams. (Artists concept.).
One prospective application: Enhancing the sensitivity of atomic magnetometers used to determine the alpha waves discharged by the human brain.
Scientists are progressively seeking to discover more about quantum entanglement, which happens when 2 or more systems are developed or connect in such a manner that the quantum states of some can not be explained independently of the quantum states of the others. Interest in studying this kind of phenomenon is due to the substantial potential for applications in encryption, communications, and quantum computing.
In the current research study by the Laboratory for Coherent Manipulation of Atoms and Light (LMCAL) at the University of São Paulos Physics Institute (IF-USP) in Brazil, the researchers was successful in establishing a source of light that produced two entangled beams. A short article on the research study was published just recently in the journal Physical Review Letters.