FROM: U.S. JUSTICE DEPARTMENT
Friday, March 28, 2014
Joint Statement by Attorney General Eric Holder and Director of National Intelligence James Clapper on the Declassification of Renewal of Collection Under Section 215 of the Usa Patriot Act (50 U.S.C. Sec. 1861))
Attorney General Eric Holder and Director of National Intelligence James Clapper released the following joint statement Friday:
“Earlier this year in a speech at the Department of Justice, President Obama announced a transition that would end the Section 215 bulk telephony metadata program as it existed, and that the government would establish a mechanism that preserves the capabilities we need without the government holding this bulk data. As a first step in that transition, the President directed the Attorney General to work with the Foreign Intelligence Surveillance Court (FISC) to ensure that, absent a true emergency, the telephony metadata can only be queried after a judicial finding that there is a reasonable, articulable suspicion that the selection term is associated with an approved international terrorist organization. The President also directed that the query results must be limited to metadata within two hops of the selection term instead of three. These two changes were put into effect on Feb. 5, 2014, when the FISC granted the government’s motion to amend its Jan. 3, 2014, primary order approving the production of telephony metadata collection under Section 215. Following a review for declassification the Jan. 3 primary order, the government’s motion to amend that order, and the order granting the motion were posted to the FISC’s website, as well as the Office of the Director of National Intelligence website and icontherecord.tumblr.com.
“In addition to directing those immediate changes to the program, the President also directed the Intelligence Community and the Attorney General to develop options for a new approach to match the capabilities and fill gaps that the Section 215 program was designed to address without the government holding this metadata. He instructed us to report back to him with options for alternative approaches before the program came up for reauthorization on March 28. Consistent with the President’s direction, we provided him with alternative approaches for consideration.
“After carefully considering the available options, the President announced yesterday that the best path forward is that the government should not collect or hold this data in bulk, and that it should remain at the telephone companies with a legal mechanism in place that would allow the government to obtain data pursuant to individual orders from the FISC approving the use of specific numbers for such queries. The President also noted that legislation would be required to implement this option.
“Given that this legislation is not yet in place, and given the importance of maintaining this capability, the President directed the Department of Justice to seek a 90-day reauthorization of the existing program, which includes the modifications that he directed in January. Consistent with both the President’s direction, and with prior declassification decisions, in light of the significant and continuing public interest in the telephony metadata collection program, DNI Clapper declassified the fact that the United States filed an application with the FISC to reauthorize the existing program as previously modified for 90 days, and that today the FISC issued an order approving the government’s application. The order issued today expires on June 20, 2014. The Administration is undertaking a declassification review of this most recent court order.
Showing posts with label DATA STORAGE. Show all posts
Showing posts with label DATA STORAGE. Show all posts
Friday, March 28, 2014
Friday, August 30, 2013
THE ARTIFICIAL SPIN GIVES A LOOK AT MAGNETIC CHARGED CRYSTALS
FROM: LOS ALAMOS NATIONAL LABORATORY
Magnetic charge crystals imaged in artificial spin ice
Potential data storage and computational advances could follow
LOS ALAMOS, N.M., August 28, 2013—A team of scientists has reported direct visualization of magnetic charge crystallization in an artificial spin ice material, a first in the study of a relatively new class of frustrated artificial magnetic materials-by-design known as “Artificial Spin Ice.” These charges are analogs to electrical charges with possible applications in magnetic memories and devices; in describing this class of materials, the new work demonstrates their utility.
Los Alamos National Laboratory staff scientist Cristiano Nisoli explained, “Magnetic technology generally concerns itself with manipulation of localized dipolar degrees of freedom,” he said. “The ability of building materials containing delocalized monopolar charges is very exciting with possible technological implications in data storage and computation.”
Honeycomb configuration helps disassemble magnetic islands
“The emergence of magnetic monopoles in spin ice systems is a particular case of what physicists call fractionalization, or deconfinement of quasi-particles that together are seen as comprising the fundamental unit of the system, in this case the north and south poles of a nanomagnet,” Nisoli said. “We have seen how arranging magnets in a honeycomb configuration allows for these charges to be sort of ‘stripped’ from the magnetic islands to which they belong and become relevant degrees of freedom.”
Nanoscale magnets prevent freezing
The unique properties of spin ice materials have fascinated scientists since they were first discovered in the late 1990s in naturally occurring rare earth titanites. The material is aptly named: the highly complex ordering of nanoscale magnets in spin ice obey the same rules that determine the positional ordering of hydrogen and oxygen atoms in frozen water ice. Both have “spin”—degrees of freedom—with frustrated interactions that prevent complete freezing, even at absolute zero.
In 2006, an interdisciplinary team of physicists and materials scientists designed the first artificial spin ice, a two-dimensional array of magnetic nanoislands that are fabricated to interact in complex ways, depending on the chosen design of the array. The islands were lithographically printed onto a substrate, arranged in a square-lattice pattern, with the north and south poles of each nanomagnet meeting and interacting at their four-pronged vertices.
New annealing process allows polarity flip
Now the same research team has developed a new annealing protocol that allows the artificial material’s full potential for highly complex magnetic interactions to be realized. The new protocol was applied to two artificial spin ice materials, one configured in a square-lattice pattern, the other in a hexagonal-honeycomb pattern with three-pronged vertices.
In the honeycomb pattern, where three magnetic poles intersect, a net charge of north or south is forced at each vertex. The magnetic “monopole charge” at each vertex influences the magnetic “charge” of the surrounding vertices. The team was able to image the crystalline structure of the magnetic charges using magnetic force microscopy.
University of Illinois physicist Peter Schiffer, who led the team, explained, “Nanomagnets are so small that their behavior becomes relatively simple. We can arrange the magnets in a particular lattice pattern—square or honeycomb—and they interact in a way that we can predict and control.”
Schiffer added, “The challenge—you have to get the nanomagnets to flip their north and south poles to show how they interact. It’s hard to force them to show the effects of interaction, since they get stuck in one particular arrangement.”
The research team’s new annealing protocol—heating the material to a high temperature where their magnetic polarity is suppressed (here, about 550 degrees Celsius) —allows the nanomagnets to flip their polarity and freely interact. As the material cools, the nanomagnets are ordered according to the interactions of their poles at the vertices.
Engineered material allows study that’s impossible in natural crystals
The collective thermal behavior of the arrays is studied through statistical mechanics, a branch of fundamental physics. As theorized, the monopole charge of each vertex was found to contribute to the order of the entire system in a manner analogous to the interactions of electric charges at the atomic scale during water ice crystal growth.
An advantage of artificial spin ice is that it can be designed in different topologies, and examined subsequently to see the effects of those topologies. That allows physicists to explore a wide range of possible behaviors that are not accessible in natural crystals.
“This work demonstrates a direction in condensed matter physics that is quite opposite to what has been done in the last six decades or so,” said Nisoli. “Instead of imagining an emergent theoretical description to model the behavior of a nature-given material and validating it indirectly, we engineer materials of desired emergent properties that can be visualized directly.”
The team’s research, led by Schiffer, also of the University of Illinois’ Frederick Seitz Materials Research Laboratory, has published its findings in the Aug. 29 issue of the journal Nature. The theoretical work for this research was performed at Los Alamos National Laboratory under Nisoli and LANL Oppenheimer Fellow Gia-Wei Chern, and at Penn State University under Vincent Crespi and Paul Lammert. The synthesis of the magnetic materials and the high temperature treatment was performed at the University of Minnesota’s Department of Chemical Engineering and Materials Science under Chris Leighton. The magnetic measurements and lithography were performed at Penn State University and the Frederick Seitz Materials Research Laboratory by graduate students Sheng Zhang and Ian Gilbert under the direction of Schiffer.
This research was supported by the U.S. Department of Energy and the National Science Foundation.
Magnetic charge crystals imaged in artificial spin ice
Potential data storage and computational advances could follow
LOS ALAMOS, N.M., August 28, 2013—A team of scientists has reported direct visualization of magnetic charge crystallization in an artificial spin ice material, a first in the study of a relatively new class of frustrated artificial magnetic materials-by-design known as “Artificial Spin Ice.” These charges are analogs to electrical charges with possible applications in magnetic memories and devices; in describing this class of materials, the new work demonstrates their utility.
Los Alamos National Laboratory staff scientist Cristiano Nisoli explained, “Magnetic technology generally concerns itself with manipulation of localized dipolar degrees of freedom,” he said. “The ability of building materials containing delocalized monopolar charges is very exciting with possible technological implications in data storage and computation.”
Honeycomb configuration helps disassemble magnetic islands
“The emergence of magnetic monopoles in spin ice systems is a particular case of what physicists call fractionalization, or deconfinement of quasi-particles that together are seen as comprising the fundamental unit of the system, in this case the north and south poles of a nanomagnet,” Nisoli said. “We have seen how arranging magnets in a honeycomb configuration allows for these charges to be sort of ‘stripped’ from the magnetic islands to which they belong and become relevant degrees of freedom.”
Nanoscale magnets prevent freezing
The unique properties of spin ice materials have fascinated scientists since they were first discovered in the late 1990s in naturally occurring rare earth titanites. The material is aptly named: the highly complex ordering of nanoscale magnets in spin ice obey the same rules that determine the positional ordering of hydrogen and oxygen atoms in frozen water ice. Both have “spin”—degrees of freedom—with frustrated interactions that prevent complete freezing, even at absolute zero.
In 2006, an interdisciplinary team of physicists and materials scientists designed the first artificial spin ice, a two-dimensional array of magnetic nanoislands that are fabricated to interact in complex ways, depending on the chosen design of the array. The islands were lithographically printed onto a substrate, arranged in a square-lattice pattern, with the north and south poles of each nanomagnet meeting and interacting at their four-pronged vertices.
New annealing process allows polarity flip
Now the same research team has developed a new annealing protocol that allows the artificial material’s full potential for highly complex magnetic interactions to be realized. The new protocol was applied to two artificial spin ice materials, one configured in a square-lattice pattern, the other in a hexagonal-honeycomb pattern with three-pronged vertices.
In the honeycomb pattern, where three magnetic poles intersect, a net charge of north or south is forced at each vertex. The magnetic “monopole charge” at each vertex influences the magnetic “charge” of the surrounding vertices. The team was able to image the crystalline structure of the magnetic charges using magnetic force microscopy.
University of Illinois physicist Peter Schiffer, who led the team, explained, “Nanomagnets are so small that their behavior becomes relatively simple. We can arrange the magnets in a particular lattice pattern—square or honeycomb—and they interact in a way that we can predict and control.”
Schiffer added, “The challenge—you have to get the nanomagnets to flip their north and south poles to show how they interact. It’s hard to force them to show the effects of interaction, since they get stuck in one particular arrangement.”
The research team’s new annealing protocol—heating the material to a high temperature where their magnetic polarity is suppressed (here, about 550 degrees Celsius) —allows the nanomagnets to flip their polarity and freely interact. As the material cools, the nanomagnets are ordered according to the interactions of their poles at the vertices.
Engineered material allows study that’s impossible in natural crystals
The collective thermal behavior of the arrays is studied through statistical mechanics, a branch of fundamental physics. As theorized, the monopole charge of each vertex was found to contribute to the order of the entire system in a manner analogous to the interactions of electric charges at the atomic scale during water ice crystal growth.
An advantage of artificial spin ice is that it can be designed in different topologies, and examined subsequently to see the effects of those topologies. That allows physicists to explore a wide range of possible behaviors that are not accessible in natural crystals.
“This work demonstrates a direction in condensed matter physics that is quite opposite to what has been done in the last six decades or so,” said Nisoli. “Instead of imagining an emergent theoretical description to model the behavior of a nature-given material and validating it indirectly, we engineer materials of desired emergent properties that can be visualized directly.”
The team’s research, led by Schiffer, also of the University of Illinois’ Frederick Seitz Materials Research Laboratory, has published its findings in the Aug. 29 issue of the journal Nature. The theoretical work for this research was performed at Los Alamos National Laboratory under Nisoli and LANL Oppenheimer Fellow Gia-Wei Chern, and at Penn State University under Vincent Crespi and Paul Lammert. The synthesis of the magnetic materials and the high temperature treatment was performed at the University of Minnesota’s Department of Chemical Engineering and Materials Science under Chris Leighton. The magnetic measurements and lithography were performed at Penn State University and the Frederick Seitz Materials Research Laboratory by graduate students Sheng Zhang and Ian Gilbert under the direction of Schiffer.
This research was supported by the U.S. Department of Energy and the National Science Foundation.
Subscribe to:
Posts (Atom)