American physicists have cooled a microscopic aluminum drum to near absolute zero, which is lower than previously thought. Researchers at the National Institute of Standards and Technology (NIST) in Colorado said the cooling technology can be used in a wide range of applications, including quantum computers or high-precision sensors. The aluminum drum, which measures 20 microns in diameter and 100 nanometers in thickness, is embedded in a chip as part of a superconducting circuit, explains John Teufel of the National Institute of Standards and Technology. To cool the aluminum drum, the researchers first placed the circuit in a vacuum chamber at a temperature of 37 Kelvin and then circulated the microwave using a circuit. Microwave photons hit the atoms in the aluminum drum and gain some momentum of the atoms. Therefore, by slowing the thermal motion of the atoms, the photons reduce the temperature of the drum to 360 micro-Kelvin temperatures. Teufel pointed out that in this experiment, the definition of temperature is different from the general definition of thermodynamics. When they say that they have reached 360 micro Kelvin, that does not mean the atom is almost stationary. On the contrary, drums are capable of vibrating over a range of frequencies, but in their experiments they have limited their vibration only at the lowest frequencies. Over the years, physicists have used photons to cool down physical systems, including atoms, molecules and even mirrors in optical cavities. However, due to Heisenberg's uncertainty principle, photon cooling power is always limited by noise. Teufel explains that in general photons acquire momentum from aluminum drum structures and occasionally they also experience "chaotic impact" due to quantum fluctuations. It has long been believed that when a photon is used to cool it produces this noise, which prevents the use of photons to cool more than a specific temperature, called the "quantum limit." The innovation of his research team is that Teufel explains that it is to find out how to get out of the noise and thus exceed the quantum limit. Researchers achieve this by using a special type of light called compressed light. Compressed light is the use of engineering uncertainty of the nature of the light. All photons follow the principle of uncertainty. For example, the more you understand the position of a photon, the less you know its momentum. Although physicists will never be able to get out of this fundamental uncertainty, they have figured out that they can redistribute it. For example, they can sacrifice the accuracy of momentum measurements if they want to know the location of photons more precisely. The team led by Teufel redistributed the uncertainty between the intensities and phases of a photon so that photons strike the aluminum drum material in a coordinated manner to eliminate random noise. He cautiously pointed out that they did not violate the rules of quantum mechanics. "We're just cleverly using rules," he said. This technique can theoretically be a cool target "arbitrarily close to" absolute zero, meaning that it is impossible to reach absolute zero and the experimenter can slowly approach the goal of confining photon quantum noise. This level of cooling means that they can observe drum vibrations due to quantum effects, which are usually submerged under thermal motion. In addition, Teufel said cooling technology can be used to make ultra-sensitive detectors such as pressure sensors or magnetic field sensors. "You can measure any change in aluminum drum material very sensitively," he said. Teufel also wants this aluminum drum structure for use in quantum computing. For example, quantum information can be encoded as a persistent vibration on the tympanic membrane. These vibrations can be used as information storage. "This job is exciting because most people in the field think they are forever blocked by quantum noises," said Aashish Clerk of McGill University in Canada, who was not involved in the job. Beyond the quantum limit, the Teufel research team really did something different. "No one has any intuitive reason to think that [compact light] actually does," Clerk said. He first heard researchers talking about this technology at a conference. This study has been published in the journal Nature.
Our company has developed STSQ5-25 ton series cranes with complete specifications and various configurations, and annual production ability is more than 8000 sets of all specifications. All our products with features such as advanced technology, excellent performance, reasonable structure, simple operation, safe use and attractive and novel appearance, and are especially suitable for engineering constructions in fields of construction site, road and bridge pipeline construction in urban and rural areas, landscape engineering, installation of power equipment, medium and small-scale water conservancy construction, etc. It is the first choice of undertake engineering construction and to enrich farmers family, Besides, our company accept customer order of different specifications special utility cranes, ship cranes, bent boom cranes and tractor cranes, which can equipped with special attachments to do other handling.
Self Make Crane, home made crane. We make the crane chassis in our workshop with high stength steel, equipped with cummins engine. It is the most popular Mobile Crane in China. Widely use for building construction, steel structure building and other hoisting works.
Self Make Crane Self Make Crane,Self Erecting Crane,Container Crane,Pick Up Boom Crane Jining Sitong Construction Machinery Co.,Ltd , http://www.cntruckcrane.com