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The Second Quantum Revolution
Published in Jonathan P. Dowling, Schrödinger’s Web, 2020
The photon-based QRNG of the first kind we discussed in chapter two. (See Figure 2.4.) A single-photon gun shoots single photons – what else? – at a 50–50 beam splitter. For each photon, we can write the quantum state after the beam splitter as |1⟩C|0⟩D+|0⟩C|1⟩D, where the notation indicates that the photon is in a cat-like superposition state of the photon going up to detector C, with nothing going to detector D, and the photon going right to detector D, with nothing going up to detector C. Written this way we can see that the state of the photon is unreal, it is not either at C or D until one of the detectors clicks, and thus the machine satisfies the second criterion for a quantum technology. Additionally, if the beam splitter is a perfect 50–50 splitter, then it is utterly uncertain which detector will click for any photon. All we can say is that 50% of the time detector C clicks – and 50% of the time detector D clicks – but which will click is unpredictable by any means. Hence the device satisfies criteria one – uncertainty. Finally, the photon is in an entangled state with nothing. More correctly, the state 0 is called the vacuum state. In quantum theory, the vacuum is not empty but instead contains zero photons, where zero photons mean something.9 The state after the beam splitter is an entangled state of one and zero photons, and hence it satisfies the third criterion – nonlocality.
Quantum effect of cooling down the environment temperature of mesoscopic LC circuit
Published in Journal of Modern Optics, 2018
In summary, we have examined the quantum mechanical effect in LC mesoscopic circuit when temperature of environment decreases, we see that the thermo vacuum state becomes to a negative binomial and the energy of the circuit in this new state increases.
Locally acting mirror Hamiltonians
Published in Journal of Modern Optics, 2021
Jake Southall, Daniel Hodgson, Robert Purdy, Almut Beige
Next, we examine the extra terms in Equation (28) which make the energy observable different from an harmonic oscillator Hamiltonian. As usual, the vacuum state is the shared zero eigenstate of all photon annihilation operators . It describes an EM field with zero energy and zero electric and magnetic field expectation values. As we can see from Equation (19), the vacuum state is also annihilated by all locally acting annihilation operators and for all parameters k, x and t. Moreover, the vacuum state is an example of the coherent states with which we parametrize as usual by complex numbers . Considering Equations (10) and (19), one can show that there are different coherent states with the same field expectation values and . For example, for real , this applies to the coherent states and with . Both coherent states describe light travelling in the same direction and it is impossible to distinguish them by looking only at their electric and magnetic field expectation values. Hence the electric and magnetic field amplitudes of a state of the form with interfere constructively. Their total energy is therefore four times as large as the energy of (cf. Equation (28)). Analogously, one can show that states of the form with have the same energy expectation value as the vacuum state. This is why the energy observable no longer coincides with a harmonic oscillator Hamiltonian.
Design and performance evaluation of a pilot-scale pulsed vacuum infrared drying (PVID) system for drying of berries
Published in Drying Technology, 2020
Wei-Peng Zhang, Chang Chen, Zhongli Pan, Hong-Wei Xiao, Long Xie, Zhen-Jiang Gao, Zhi-An Zheng
In recent years, the application of IR heating in the vacuum drying process has drawn increased research interests.[14] Due to its high energy intensity and penetrability, IR heating has been widely studied for the drying of different agricultural products.[15] Compared with the ambient condition, transmission of IR radiation is usually improved in the vacuum state due to the lower amount of water vapor (H2O) and carbon dioxide (CO2), which absorb the IR energy.[16] As a result, the rate of mass and heat transfer is increased. Three types of IR emitters are commonly used in commercial operations: natural gas emitter, quartz emitter, and ceramic emitter.[17] Pan et al. designed and developed a sequential infrared and freeze-drying system with natural gas emitter and investigated the drying characteristics and quality of banana slices,[18, apple slices,[19] and blueberries.[20] Results showed that IR drying could maintain the natural color and retain nearly 50% vitamin C. Aidani et al.[21] evaluated the drying characteristics of kiwifruit slice using a quartz emitter infrared-vacuum drying system. In their study, with an increase of input IR power from 200 to 300 W, the effective moisture diffusivity increased from 1.04 × 10−9 to 2.29 × 10−9 m2/s. Salehi et al.[22] studied the ceramic emitter characteristics and used infrared-vacuum drying to produce high-quality mushroom slices. The drying time was reduced from 300 to 40 min as the IR power increased from 83 to 209 W. However, these IR emitters are usually large in size, complex in configuration, and difficult to be installed in a vacuum chamber.[23] In recent years, a new type of IR emitter made from carbon fiber sheet was developed.[24] The thickness of this new IR emitter is only 2–4 mm and can be activated by regular voltage (220 V/110 V) easily. Compared to the conventional ceramic emitter, quartz emitter, or gas combustion emitter, this new emitter has a relatively simple configuration, thinner thickness, and more compact volume, which makes it easy to be installed in limited space.[25] Moreover, without the combustion of flammable gas and air ventilation, it is safer for operation. The power density of carbon fiber sheet IR emitter is lower, and the drying temperature can be controlled precisely and easily.[26] In summary, these advantages can be used favorably to optimize the design of the vacuum drying chamber and control system. Proper design of pulsed vacuum infrared drying (PVID) with the advantages of PVD and IR heating is considered being more efficient over the single technology, as it provides a synergistic effect and improves the heat and mass transfer of berries during the drying process.