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Primeur weekly 2013-09-02

Focus

Using one Cloud for Cloud computing today? Perhaps two Clouds? In the future there will be MultiClouds. An interview with Dana Petcu of the West University of Timisoara ...

The Cloud

VMware delivers vCloud Hybrid Service ...

HP and SAP collaborate to deliver HP As-a-Service solution for SAP HANA ...

Dell delivers innovative Cloud and virtualization solutions blending VMware technology with Dell end-to-end offerings ...

New FICO software enables data scientists to transform Big Data into predictive models ...

Smart is the new green in Latin America ...

VMware management solutions demonstrated on stage at VMworld ...

HP and Yorkshire Building Society boost agility for financial services providers ...

IBM closes acquisition of CSL International ...

University of California deploys Huawei's Cloud storage system to support computational astrophysics research ...

Desktop Grids

Neutron stars in the computer Cloud ...

EuroFlash

Video Design brings Dataton WATCHOUT and WATCHPAX to InfoComm India 2013 ...

New UK/USA agreement will use high performance computing to boost economic competitiveness ...

Immanuel Bloch is to receive the Körber Prize 2013 ...

Light on twenty-year-old mystery ...

University of Tübingen physicists create interface between atoms and superconductors ...

USFlash

Allinea tools help Canada close innovation gap ...

Dell furthers commitment to Asia with transformative technology solutions from the data centre to the end device ...

Control scheme dynamically maintains unstable quantum system ...

Hadoop release 2.1.0-beta available ...

Mapping the Earth's magnetosphere to predict and prepare for space-weather events ...

EMC and VMware join forces around software-defined storage and VMware virtual SAN ...

HP and VMware enable customers to unify data centre networks ...

OSC hosts first meeting of the MVAPICH Users Group ...

Vampir takes a bite out of inefficiency as codes run on bigger supercomputers ...

HP helps HoneyBaked Ham of Georgia manage seasonal demand via tenfold performance boost ...

Control scheme dynamically maintains unstable quantum system


Georgia Tech - John Toon
27 Aug 2013 Atlanta - A simple pendulum has two equilibrium points: hanging in the "down" position and perfectly inverted in the "up" position. While the "down" position is a stable equilibrium, the inverted position is definitely not stable. Any infinitesimal deviation from perfectly inverted is enough to cause the pendulum to eventually swing down. It has been known for more than 100 years, though, that an inverted pendulum can be stabilized by vibrating the pivot point. This non-intuitive phenomenon is known as dynamic stabilization, and it has led to a broad range of applications including charged particle traps, mass spectrometers and high-energy particle accelerators.

Many-body quantum systems can also be placed into unstable non-equilibrium states, and like the inverted pendulum of classical physics, they typically evolve away from these states. Now, researchers at the Georgia Institute of Technology have demonstrated a way to maintain an unstable quantum system by applying bursts of microwave radiation - a quantum analogue to vibrating the inverted pendulum.

In an experiment that could have implications for quantum computers and quantum simulators, the researchers used microwave pulses of varying amplitudes and frequencies to control a quantum system composed of a cloud of approximately 40,000 rubidium atoms cooled nearly to absolute zero.

The research, sponsored by the National Science Foundation and reported on-line August 27 by the journalPhysical Review Letters, experimentally demonstrated dynamical stabilization of a non-equilibrium many-body quantum system. The paper is scheduled to appear in the journal's August 30 print issue.

"In this work, we have demonstrated that we can control the quantum dynamics of a cloud of atoms to maintain them in a non-equilibrium configuration analogous to the inverted pendulum", stated Michael Chapman, a professor in the Georgia Tech School of Physics. "What we actually control is the internal spins of the atoms that give each atom a small magnetic moment. The spins are oriented in an external magnetic field against their will such that they would prefer to flip their orientation to the equilibrium position."

Mathematically, the state of the rubidium atoms is virtually identical to that of the simple mechanical pendulum, meaning that Michael Chapman and his students have controlled what could be called a "quantum inverted pendulum".

In their experiment, the researchers began with a spin-1 atomic Bose-Einstein condensate (BEC) that is initialized in an unstable, fixed point of the spin-nematic phase space - comparable to an inverted pendulum. If allowed to freely evolve, interactions between the atoms would give rise to squeezing, quantum spin mixing and eventually relaxation to a stable state - comparable to a pendulum hanging straight down from a pivot point.

By periodically applying bursts of microwave radiation, the researchers rotated the spin-nematic many-body fluctuations, halting the squeezing and the relaxation toward stability. The researchers investigated a range of pulse periods and phase shifts to map a stability diagram that compares well with what they expected theoretically.

"The net effect is that the many-body system basically returns to the original state", stated Michael Chapman. "We reverse the squeezing of the condensate, and after it again evolves toward squeezing, we cause it to return. If we do this periodically, we can maintain the Bose-Einstein condensate in this unstable point indefinitely."

The control technique differs from active feedback, which measures the direction in which a system is moving and applies a force counter to that direction. The open-loop technique used by Michael Chapman's group applies a constant input that doesn't vary with the activity of the system being controlled.

"We are periodically kicking the system to keep it in a state where it doesn't want to be", he stated. "This is the first time we have been able to make a many-body spin system that we can stabilize against its natural evolution."

Controlling and manipulating single-particle quantum systems or simple collections of atoms, electrons and photons has been a focus of the physics community over recent decades. These capabilities have formed the foundation for technologies such as lasers, magnetic resonance imaging, atomic clocks and new atomic sensors for magnetic fields and inertial guidance.

Now, researchers are studying more complex systems that involve many additional interacting particles, perhaps thousands of them. Michael Chapman and his group hope to help extend their knowledge of these more complex many-body systems, which could lead to developments in quantum computing, quantum simulations and improved measurements.

"The long-range goal of our work is to further the understanding of quantum mechanics and to develop new technologies that exploit the often counter-intuitive realities of the quantum world", Michael Chapman stated. "Quantum many-body systems are being actively explored, and one of the things you'd like to do is be able to control them. I think this is one of the cleanest examples of being able to control a quantum many-body system in a manifestly unstable configuration."

In addition to Michael Chapman, other co-authors of the paper include T.M. Hoang, C.S. Gerving, B.J. Land, M. Anquez and C.D. Hamley. This research is supported by the National Science Foundation (NSF) under Award PHY-1208828.

Source: Georgia Institute of Technology

Back to Table of contents

Primeur weekly 2013-09-02

Focus

Using one Cloud for Cloud computing today? Perhaps two Clouds? In the future there will be MultiClouds. An interview with Dana Petcu of the West University of Timisoara ...

The Cloud

VMware delivers vCloud Hybrid Service ...

HP and SAP collaborate to deliver HP As-a-Service solution for SAP HANA ...

Dell delivers innovative Cloud and virtualization solutions blending VMware technology with Dell end-to-end offerings ...

New FICO software enables data scientists to transform Big Data into predictive models ...

Smart is the new green in Latin America ...

VMware management solutions demonstrated on stage at VMworld ...

HP and Yorkshire Building Society boost agility for financial services providers ...

IBM closes acquisition of CSL International ...

University of California deploys Huawei's Cloud storage system to support computational astrophysics research ...

Desktop Grids

Neutron stars in the computer Cloud ...

EuroFlash

Video Design brings Dataton WATCHOUT and WATCHPAX to InfoComm India 2013 ...

New UK/USA agreement will use high performance computing to boost economic competitiveness ...

Immanuel Bloch is to receive the Körber Prize 2013 ...

Light on twenty-year-old mystery ...

University of Tübingen physicists create interface between atoms and superconductors ...

USFlash

Allinea tools help Canada close innovation gap ...

Dell furthers commitment to Asia with transformative technology solutions from the data centre to the end device ...

Control scheme dynamically maintains unstable quantum system ...

Hadoop release 2.1.0-beta available ...

Mapping the Earth's magnetosphere to predict and prepare for space-weather events ...

EMC and VMware join forces around software-defined storage and VMware virtual SAN ...

HP and VMware enable customers to unify data centre networks ...

OSC hosts first meeting of the MVAPICH Users Group ...

Vampir takes a bite out of inefficiency as codes run on bigger supercomputers ...

HP helps HoneyBaked Ham of Georgia manage seasonal demand via tenfold performance boost ...