Localized thermal emission from topological interfaces Ergoktas, M. Said; Kecebas, Ali; Despotelis, Konstantinos ...
Science (American Association for the Advancement of Science),
06/2024, Letnik:
384, Številka:
6700
Journal Article
Recenzirano
The control of thermal radiation by shaping its spatial and spectral emission characteristics plays a key role in many areas of science and engineering. Conventional approaches to tailoring thermal ...emission using metamaterials are hampered both by the limited spatial resolution of the required subwavelength material structures and by the materials’ strong absorption in the infrared. In this work, we demonstrate an approach based on the concept of topology. By changing a single parameter of a multilayer coating, we were able to control the reflection topology of a surface, with the critical point of zero reflection being topologically protected. The boundaries between subcritical and supercritical spatial domains host topological interface states with near-unity thermal emissivity. These topological concepts enable unconventional manipulation of thermal light for applications in thermal management and thermal camouflage.
Editor’s summary Many applications in science and engineering rely on the ability to regulate and control the thermal environment. Ergoktas et al . introduce a topological route to control the thermal properties of a cavity system. The authors show that by controlling the geometric parameters of the cavity, they can effectively tune a topological property that regulates thermal emission from the cavity surface. These results illustrate a new approach to engineering the thermal properties of materials for applications in thermal management, energy harvesting, and thermal camouflage. —Ian S. Osborne
Abstract
Background
This study was conducted to determine the health literacy levels and related factors of the patients who applied to a health unit.
Methods
The population of this cross-sectional ...study was the patients who applied to a district outpatient clinic in the center of Malatya. Power 80% and in the 95% confidence interval based on the mean of health literacy scale of Turkey (29.5 ± 5.7) the sample size was determined as 317. In the first three months of 2019 outpatients and 384 randomized patients who agreed to participate in the study, developed by the Ministry of Health Literacy Turkey Health Questionnaire-32 (THLQ) was applied. The score obtained from the scale is considered to be insufficient of 25 and below, limited to > 25-33 points and a score of < 33 and above is sufficient. In the analysis of the data, Kolmogorov Smirnov, Mann Whitney U, Kruskal Wallis and Chi-Kare tests were used and p < 0.05 was chosen as the level of error.
Results
49.9% of the participants were male and 50.1% were female. The average age is 35.94 ± 13.8. While 24% of the participants have secondary or lower education, 40.6% are graduates of higher education. In this study,the health literacy scale mean score of the participants is 15.85 ± 11.07. According to the results of THLQ-32, 78.1% of the participants were in the “insufficient” health literacy category, 14.0% in the “limited” category, only 7.9% in the “sufficient” category. Gender, age, educational background, frequency of applying to the health institution were determined as factors affecting the level of health literacy (p < 0.05). However, the presence of a disease causing regular drug use was not identified as a related factor (p > 0.05).
Conclusions
In this study, although of have a high education level of the participants were found to be inadequate of health literacy levels according to Turkey average value reflects the general.
Key messages
According to these results, it may be difficult for the groups that are insufficient in terms of health literacy to benefit from health services. Raising the health literacy level of the society can be an important component of health promotion.
Non‐hermitian spectral degeneracies, known as exceptional points (EPs), feature the simultaneous coalescence of both eigenvalues and the associated eigenstates of a system. A host of intriguing EP ...effects and their applications have been revealed in the classical realm, such as loss‐induced lasing, single‐mode laser, and EP‐enhanced sensing. Here, it is shown that a purely quantum effect, known as single‐photon blockade, emerges in a Kerr microring resonator due to EP‐induced asymmetric coupling between the optical modes and the nonlinearity‐induced anharmonic energy‐level spacing. A striking feature of this photon blockade is that it emerges at two‐photon resonance which in Hermitian systems will only lead to photon‐induced tunneling but not to photon blockade. By tuning the system towards or away from an EP, one can control quantum correlations, implying the potential use of their system for frequency tunable single‐photon generation and an antibunching‐to‐bunching light switch. The work sheds new light on EP‐engineered purely quantum effects, providing unique opportunities for making and utilizing various single‐photon quantum EP devices.
Chiral exceptional points (EPs) can emerge by controlling the relative angular position of two nanotips placed near an optical Kerr resonator. The interplay of EPs and Kerr nonlinearity leads to the counterintuitive effect of two‐photon resonance antibunching. Also, frequency‐tunable photon blockade can be achieved in such a quantum non‐Hermitian device.
Abstract Quantum random number generators employ the inherent randomness of quantum mechanics to generate truly unpredictable random numbers, which are essential in cryptographic applications. While ...a great variety of quantum random number generators have been realized using photonics, few exploit the high-field confinement offered by plasmonics, which enables device footprints an order of magnitude smaller in size. Here we integrate an on-chip nanowire plasmonic waveguide into an optical time-of-arrival based quantum random number generation setup. Despite loss, we achieve a random number generation rate of 14.4 Mbits s − 1 using low light intensity, with the generated bits passing industry standard tests without post-processing. By increasing the light intensity, we were then able to increase the generation rate to 41.4 Mbits s − 1 , with the resulting bits only requiring a shuffle to pass all tests. This is an order of magnitude increase in the generation rate and decrease in the device size compared to previous work. Our experiment demonstrates the successful integration of an on-chip nanoscale plasmonic component into a quantum random number generation setup. This may lead to new opportunities in compact and scalable quantum random number generation.
PT -symmetric circuit QED Quijandría, Fernando; Naether, Uta; Özdemir, Sahin K. ...
Physical review. A,
05/2018, Letnik:
97, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A parity-time (PT)-symmetric system emerging from a quantum dynamics is highly desirable in order to understand the possible implications of PT symmetry in the next generation of quantum ...technologies. In this work, we address this need by proposing and studying a circuit-QED architecture that consists of two coupled resonators and two qubits (each coupled to one resonator). By means of external driving fields on the qubits, we are able to tune gains and losses in the resonators. Starting with the quantum dynamics of this system, we show the emergence of the PT symmetry via the selection of both driving amplitudes and frequencies. We engineer the system such that a non-number-conserving dipole-dipole interaction emerges, introducing an instability at large coupling strengths. The PT symmetry and its breaking, as well as the predicted instability in this circuit-QED system, can be observed in a transmission experiment.
Quantum heat engines are expected to outperform the classical counterparts due to quantum coherences involved. Here we experimentally execute a single-ion quantum heat engine and demonstrate, for the ...first time, the dynamics and the enhanced performance of the heat engine originating from the Liouvillian exceptional points (LEPs). In addition to the topological effects related to LEPs, we focus on thermodynamic effects, which can be understood by the Landau-Zener-Stückelberg process under decoherence. We witness a positive net work from the quantum heat engine if the heat engine cycle dynamically encircles a LEP. Further investigation reveals that a larger net work is done when the system is operated closer to the LEP. We attribute the enhanced performance of the quantum heat engine to the Landau-Zener-Stückelberg process, enabled by the eigenenergy landscape in the vicinity of the LEP, and the exceptional point-induced topological transition. Therefore, our results open new possibilities toward LEP-enabled control of quantum heat engines and of thermodynamic processes in open quantum systems.
Quantum plasmonics Tame, M. S.; McEnery, K. R.; Özdemir, Ş. K. ...
Nature physics,
06/2013, Letnik:
9, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Quantum plasmonics is a rapidly growing eld of research that involves the study of the quantum properties of light and its interaction with matter at the nanoscale. Here, surface ...plasmonselectromagnetic excitations coupled to electron charge density waves on metaldielectric interfaces or localized on metallic nanostructuresenable the connement of light to scales far below that of conventional optics. We review recent progress in the experimental and theoretical investigation of the quantum properties of surface plasmons, their role in controlling lightmatter interactions at the quantum level and potential applications. Quantum plasmonics opens up a new frontier in the study of the fundamental physics of surface plasmons and the realization of quantum-controlled devices, including single-photon sources, transistors and ultra-compact circuitry at the nanoscale.
The concept of exceptional points-based optical amplifiers (EPOAs) has been recently proposed as a new paradigm for miniaturizing optical amplifiers while simultaneously enhancing their ...gain-bandwidth product. While the operation of this new family of amplifiers in the classical domain provides a clear advantage, their performance in the quantum domain has not yet been evaluated. Particularly, it is not clear how the quantum noise introduced by vacuum fluctuations will affect their operation. Here, we investigate this problem by considering three archetypal EPOA structures that rely either on unidirectional coupling, parity-time symmetry, or particle-hole symmetry for implementing the exceptional point. By using the Heisenberg-Langevin formalism, we calculate the added quantum noise in each of these devices and compare it with that of a quantum-limited amplifier scheme that does not involve any exceptional points. Our analysis reveals several interesting results: most notably that while the quantum noise of certain EPOAs can be comparable to those associated with conventional amplifier systems, in general the noise does not follow a universal scaling as a function of the exceptional point but rather varies from one implementation to another.
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