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Latest News and Research

A graphic that explains how the new interface works.
Nanoscale cavity strongly links quantum particles
Single photons can quickly modify individual electrons embedded in a semiconductor chip and vice versa

Today’s networks use electronic circuits to store information and optical fibers to carry it, and quantum networks may benefit from a similar framework. Such networks would transmit qubits – quantum versions of ordinary bits – from place to place and would offer unbreakable security for the transmitted information. But researchers must first develop ways for qubits that are better at storing information to interact with individual packets of light called photons that are better at transporting it, a task achieved in conventional networks by electro-optic modulators that use electronic signals to modulate properties of light. Now, researchers in the group of Edo Waks have struck upon an interface between photons and single electrons that makes progress toward such a device. Continue Reading

Jay Deep Sau Receives National Science Foundation CAREER Award

Jay Deep Sau, an assistant professor of physics at the University of Maryland and fellow of the Joint Quantum Institute, received a Faculty Early Career Development (CAREER) Award from the National Science Foundation (NSF) for his proposal titled “Topologically Protected Quantum Devices.” Sau, a theoretical condensed matter physicist interested in applying topological principles to create protected solid-state and cold-atomic systems for quantum information processing, will use the $443,908 award to build a research program focused on predicting phenomena that could help pave the way for topological quantum computation.Continue Reading

Sankar Das Sarma included on Thomson Reuter’s 2015 list of Highly Cited Researchers

Two researchers from the University of Maryland's College of Computer, Mathematical, and Natural Sciences are included on Thomson Reuter’s 2015 list of Highly Cited Researchers, a compilation of influential names in science.

Beating the heat
Ultrafast sensing and quantum control

Harnessing quantum systems for information processing will require controlling large numbers of basic building blocks called qubits. The qubits must be isolated, and in most cases cooled such that, among other things, errors in qubit operations do not overwhelm the system, rendering it useless. Led by JQI Fellow Christopher Monroe, physicists have recently demonstrated important steps towards implementing a proposed type of gate, which does not rely on super-cooling their ion qubits. This work, published as an Editor’s Suggestion in Physical Review Letters, implements ultrafast sensing and control of an ion's motion, which is required to realize these hot gates. Notably, this experiment demonstrates thermometry over an unprecedented range of temperatures--from zero-point to...Continue Reading

Controlling the Thermodynamics of Light
The concept of chemical potential can apply to light

The concept of temperature is critical in describing many physical phenomena, such as the transition from one phase of matter to another. Turn the temperature knob and interesting things can happen. But other knobs might be just as important for studying some phenomena. One such knob is chemical potential, a thermodynamic parameter first introduced in the nineteenth century by scientists for keeping track of potential energy absorbed or emitted by a system during chemical reactions.

In these reactions different atomic species rearranged themselves into new configuration while conserving the overall inventory of atoms. That is, atoms could change their partners but the total number of identity of the atoms remained invariant.Continue Reading

Shaking Bosons into Fermions

Particles can be classified as bosons or fermions. A defining characteristic of a boson is its ability to pile into a single quantum state with other bosons. Fermions are not allowed to do this. One broad impact of fermionic anti-social behavior is that it allows for carbon-based life forms, like us, to exist. If the universe were solely made from bosons, life would certainly not look like it does. Recently, JQI theorists* have proposed an elegant method for achieving transmutation--that is, making bosons act like fermions. This work was published in the journal Physical Review Letters.

This transmutation is an example of emergent behavior, specifically what’s known as quasiparticle excitations—one of the concepts that make...Continue Reading

Quantum Insulation
Intemperate atoms can't come to equilibrium

Two physical phenomena, localization and ergodicity-breaking, are conjoined in new experimental and theoretical work.  Before we consider possible implications for fundamental physics and for prospective quantum computing, let’s first look at these two topics in turn.  It will bear providing some specific examples before getting to the quantum details.

 LOCALIZATION

When electrons pass through a material they encounter various degrees of resistance, causing them to lose energy along their journey.  In the 1950s physicist Philip Anderson, predicted that in some disordered materials (such as a semiconductors) electrons---or more specifically the electrons viewed as a series of quantum waves---could get trapped.  ...Continue Reading

Photon-counting calibrations
Calibrating an optical attenuator with few-photon pulses

From NIST-PML — Precise measurements of optical power enable activities from fiber-optic communications to laser manufacturing and biomedical imaging — anything requiring a reliable source of light. This situation calls for light-measuring (radiometric) standards that can operate over a wide range of power levels.

Currently, however, different methods for calibrating optical power measurements are required for different light levels. At high levels, existing radiometric standards employ analog detectors, diodes that generate a current proportional to the incident light intensity, but become imprecise at low levels. Low-power detectors, by contrast, very accurately measure discrete (usually very small) numbers of photons, but cannot handle light at higher levels...Continue Reading

Latest News and Research

  • A graphic that explains how the new interface works.
    Nanoscale cavity strongly links quantum particles
    Single photons can quickly modify individual electrons embedded in a semiconductor chip and vice versa

    Today’s networks use electronic circuits to store information and optical fibers to carry it, and quantum networks may benefit from a similar framework. Such networks would transmit qubits – quantum versions of ordinary bits – from place to place and would offer unbreakable security for the transmitted information. But researchers must first develop ways for qubits that are better at storing... Continue Reading

  • Jay Deep Sau Receives National Science Foundation CAREER Award

    Jay Deep Sau, an assistant professor of physics at the University of Maryland and fellow of the Joint Quantum Institute, received a Faculty Early Career Development (CAREER) Award from the National Science Foundation (NSF) for his proposal titled “Topologically Protected Quantum Devices.” Sau, a theoretical condensed matter physicist interested in applying topological principles to create... Continue Reading

  • Sankar Das Sarma included on Thomson Reuter’s 2015 list of Highly Cited Researchers

    Two researchers from the University of Maryland's College of Computer, Mathematical, and Natural Sciences are included on Thomson Reuter’s 2015 list of Highly Cited Researchers, a compilation of influential names in science.

  • Beating the heat
    Ultrafast sensing and quantum control

    Harnessing quantum systems for information processing will require controlling large numbers of basic building blocks called qubits. The qubits must be isolated, and in most cases cooled such that, among other things, errors in qubit operations do not overwhelm the system, rendering it useless. Led by JQI Fellow Christopher Monroe, physicists have recently demonstrated important steps towards... Continue Reading

  • Controlling the Thermodynamics of Light
    The concept of chemical potential can apply to light

    The concept of temperature is critical in describing many physical phenomena, such as the transition from one phase of matter to another. Turn the temperature knob and interesting things can happen. But other knobs might be just as important for studying some phenomena. One such knob is chemical potential, a thermodynamic parameter first introduced in the nineteenth century by scientists for... Continue Reading

  • Shaking Bosons into Fermions

    Particles can be classified as bosons or fermions. A defining characteristic of a boson is its ability to pile into a single quantum state with other bosons. Fermions are not allowed to do this. One broad impact of fermionic anti-social behavior is that it allows for carbon-based life forms, like us, to exist. If the universe were solely made from bosons, life would certainly... Continue Reading

  • Quantum Insulation
    Intemperate atoms can't come to equilibrium

    Two physical phenomena, localization and ergodicity-breaking, are conjoined in new experimental and theoretical work.  Before we consider possible implications for fundamental physics and for prospective quantum computing, let’s first look at these two topics in turn.  It will bear providing some specific examples before getting to the quantum details.

     L... Continue Reading

  • Photon-counting calibrations
    Calibrating an optical attenuator with few-photon pulses

    From NIST-PML — Precise measurements of optical power enable activities from fiber-optic communications to laser manufacturing and biomedical imaging — anything requiring a reliable source of light. This situation calls for light-measuring (radiometric) standards that can operate over a wide range of power levels.

    Currently, however, different methods for calibrating... Continue Reading

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