## Emanuel H Knill## National Institute of Standards and Technology, Boulder, CO, USA | Center for Theory of Quantum Matter, University of Colorado, Boulder, CO, USA | National Institute of ... | |

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## Emanuel H Knill:Expert Impact

Concepts for which**Emanuel H Knill**has direct influence:**Probability estimation**,**Local realism**,**Quantum computing**,**Trapped ions**,**Universal control**,**Noiseless subsystems**,**Quantum error correction**,**Quantum systems**.

## Emanuel H Knill:KOL impact

Concepts related to the work of other authors for whichfor which Emanuel H Knill has influence:**Quantum computation**,**Single photons**,**Trapped ions**,**Error correction**.

## KOL Resume for Emanuel H Knill

Year | |
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2021 | National Institute of Standards and Technology, Boulder, CO, USA |

2020 | Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA. National Institute of Standards and Technology, Boulder, Colorado 80305, USA |

2018 | National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA. Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA |

2017 | National Institute of Standards and Technology (NIST), 80305, Boulder, Colorado, USA |

2015 | National Institute of Standards and Technology, Boulder, Colorado, 80305, USA |

2014 | National Institute of Standards and Technology, 325 Broadway, 80305, Boulder, Colorado, USA |

2013 | National Institute of Standards and Technology, Boulder, CO 80305, USA |

2012 | National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA |

2010 | Mathematical and Computational Sciences Division, National Institute of Standards and Technology, Boulder, Colorado, 80305, USA |

2008 | National Institute of Standards and Technology, MC 891, 325 Broadway, Boulder, Colorado 80305, USA |

2007 | Mathematical and Computational Sciences Division, National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA |

2006 | National Institute for Standards and Technology, 325 Broadway, Boulder/CO 80305, USA |

2005 | Mathematical and Computational Sciences Division, National Institute of Standards and Technology, Boulder Colorado 80305, USA |

2004 | Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA |

2003 | Theoretical Division, Los Alamos National Laboratory, Los Alamos, P.O. Box 1663, NM 87545, USA Los Alamos National Laboratory, Mail Stop B256, Los Alamos, New Mexico 87545 |

2002 | Los Alamos National Laboratories, Los Alamos, New Mexico 87545 |

2001 | Los Alamos National Laboratory, MS B265, Los Alamos, New Mexico 87545 |

2000 | Theoretical Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87455 Los Alamos National Laboratory, Los Alamos, NM, 87545, USA |

1999 | Computer Research and Applications CIC-3, MS B-265, Los Alamos National Laboratory, 87455, Los Alamos, NM Theoretical Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexıco 87455 |

1998 | Computer Research and Applications CIC-3, MS B-265, Los Alamos National Laboratory, 87545, Los Alamos, New Mexico, USA MS B265, Los Alamos National Laboratory, Los Alamos, New Mexico 87455 |

1997 | CIC-3, Mail Stop B265, Los Alamos National Laboratory, New Mexico 87545 |

1996 | Los Alamos National Laboratory, New Mexico 87545, USA. |

1995 | Center for Human Genome Studies, CIC-3, Computer Research and Applications, Mailstop K990, Computing, Information, and Communications Division, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA |

Concept | World rank |
---|---|

“noise” dynamics error | #1 |

physics problems quantum | #1 |

channel capacities equivalence | #1 |

goal physics simulation | #1 |

1024 random bits | #1 |

nonlocality bell violation | #1 |

previous measurement settings | #1 |

state current iteration | #1 |

random decoupling protocols | #1 |

bernoulli trials | #1 |

illustrative case presence | #1 |

randomness beacons11 | #1 |

“subsystems principle quantum | #1 |

excessive resource overheads | #1 |

success linear optics | #1 |

energy relaxation dephasing | #1 |

solution entanglement | #1 |

letter hongoumandel interference | #1 |

modes probability | #1 |

certifying quantum | #1 |

error algebra | #1 |

highquality private sources | #1 |

epgs cent | #1 |

procedure unique estimation | #1 |

values pbr values | #1 |

verification noiseless subsystems | #1 |

large detectederror rates | #1 |

zalka | #1 |

noninteracting bosonic atoms | #1 |

neutral atoms postselection | #1 |

channel capacity availability | #1 |

arbitrary stopping rules | #1 |

errors qubits | #1 |

quantum dynamics goal | #1 |

undetected error event | #1 |

realistic control resources | #1 |

algorithm stopping rules | #1 |

signed directed distances | #1 |

ancilla states gottesman | #1 |

procedure quantum states | #1 |

decoding pool | #1 |

method stabilizer state | #1 |

stopping rules context | #1 |

independent latency | #1 |

local realism tests | #1 |

subsystems quantum operation | #1 |

subsystem desired quantum | #1 |

noisy devices gates | #1 |

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**Prominent publications by Emanuel H Knill**

Scalable quantum computation1 and communication require error control to protect quantum information against unavoidable noise. Quantum error correction2,3 protects information stored in two-level **quantum systems** (qubits) by rectifying errors with **operations conditioned** on the measurement outcomes. Error-correction protocols have been implemented in **nuclear magnetic resonance** experiments4,5,6, but the inherent limitations of this technique7 prevent its application to quantum information ...

Known for | Quantum Error | Initial State | Ancilla Qubits | Measurement OutcomesUnavoidable Noise |

Quantum error correction will be necessary for preserving **coherent states** against noise and other unwanted interactions in **quantum computation** and communication. We develop a **general theory** of **quantum error** correction based on encoding states into larger Hilbert spaces subject to known interactions. We obtain necessary and **sufficient conditions** for the perfect recovery of an **encoded state** after its degradation by an interaction. The conditions depend only on the behavior of the logical ...

Known for | Correcting Codes | Quantum Error | Entangled States | Tensor ProductsLower Bounds |

Characterizing and quantifying quantum correlations in states of many-particle systems is at the core of a full understanding of **phase transitions** in matter. In this work, we continue our investigation of the notion of **generalized entanglement** [Barnum , Phys. Rev. A 68, 032308 (2003)] by focusing on a simple Lie-algebraic measure of purity of a **quantum state** relative to an observable set. For the algebra of local observables on multi-qubit systems, the resulting local **purity measure** is ...

Known for | Phase Transitions | Generalized Entanglement | Quantum Correlations | Solvable ModelsTransverse Magnetic Field |

Nuclear magnetic resonance (NMR) provides an experimental setting to explore physical implementations of quantum information processing (QIP). Here we introduce the basic background for understanding applications of NMR to QIP and explain their current successes, limitations and potential. NMR spectroscopy is well known for its wealth of diverse coherent manipulations of spin dynamics. Ideas and instrumentation from **liquid state** NMR spectroscopy have been used to experiment with QIP. ...

Known for | Nmr Qip | Based Quantum | Physical Implementations | Nuclear Magnetic ResonanceLiquid State |

We describe efficient methods for screening clone libraries, based on pooling schemes that we call "random k-sets designs." In these designs, the pools in which any clone occurs are equally likely to be any possible selection of k from the v pools. The values of k and v can be chosen to optimize desirable properties. Random k-sets designs have substantial advantages over alternative pooling schemes: they are efficient, flexible, and easy to specify, require fewer pools, and have ...

Known for | Pooling Design | Library Screening | Pools Clone | Human PairSubstantial Advantages |

In bulk quantum computation one can manipulate a large number of indistinguishable quantum computers by parallel unitary operations and measure **expectation values** of certain observables with limited sensitivity. The **initial state** of each computer in the ensemble is known but not pure. Methods for obtaining effective pure **input states** by a series of manipulations have been described by Gershenfeld and Chuang (logical labeling) [Science 275, 350 (1997)] and Cory et al. (spatial averaging) ...

Known for | Quantum Computation | Effective Pure States | Nuclear Magnetic Resonance | Temporal AveragingInitial State |

Quantum computers promise to increase greatly the efficiency of solving problems such as factoring large integers, combinatorial optimization and quantum physics simulation. One of the greatest challenges now is to implement the basic quantum-computational elements in a physical system and to demonstrate that they can be reliably and scalably controlled. One of the earliest proposals for **quantum computation** is based on implementing a quantum bit with two **optical modes** containing one ...

Known for | Efficient Quantum Computation | Linear Optics | Optical Modes | Basic ElementsBeam Splitters |

Unentangled pure states on a bipartite system are exactly the coherent states with respect to the group of local transformations. What aspects of the study of entanglement are applicable to generalized coherent states? Conversely, what can be learned about entanglement from the well-studied theory of coherent states? With these questions in mind, we characterize unentangled pure states as extremal states when considered as linear functionals on the local Lie algebra. As a result, a ...

Known for | Coherent States | Study Entanglement | Local Operations | General SettingCondensed Matter |

A key requirement for scalable quantum computing is that elementary **quantum gates** can be implemented with sufficiently low error. One method for determining the error behavior of a **gate implementation** is to perform process tomography. However, standard **process tomography** is limited by errors in state preparation, measurement and one-qubit gates. It suffers from inefficient scaling with number of qubits and does not detect adverse error-compounding when gates are composed in long ...

Known for | Quantum Gates | Randomized Benchmarking | Long Sequences | Process TomographyState Preparation |

Schrödinger's atomic catsSchrödinger's hypothetical cat was both dead and alive thanks to a paradox of quantum mechanics, in which a system exists in two or more states at once in a ‘superposition’ of entangled states. Creating this situation experimentally is very difficult, especially for systems made up of many particles, as interactions with the environment destroy superposition in a process called decoherence. So far, entangled states of just a handful of atoms or photons have been ...

Known for | Entangled States | Ion Trap | Quantum Mechanics | Electromagnetic FieldSchrödinger State |

For pt.I see ibid., vol.46, no.3, p.778-88 (2000). In Part I of this paper we formulated the problem of error detection with **quantum codes** on the **depolarizing channel** and gave an expression for the probability of undetected error via the **weight enumerators** of the code. In this part we show that there exist quantum codes whose probability of undetected error falls exponentially with the length of the code and derive bounds on this exponent. The lower (existence) bound is proved for ...

Known for | Error Detection | Quantum Codes | Upper Bounds | Linear ProgrammingWeight Enumerators |

### Liquid-state nuclear magnetic resonance as a testbed for developing quantum control methods

[ PUBLICATION ]

In building a quantum-information processor (QIP), the challenge is to coherently control a large quantum system well enough to perform an arbitrary quantum algorithm and to be able to correct errors induced by decoherence. Nuclear magnetic resonance (NMR) QIPs offer an **excellent testbed** on which to develop and **benchmark tools** and techniques to control quantum systems. Two main issues to consider when designing **control methods** are accuracy and efficiency, for which two complementary ...

Known for | Control Methods | Nuclear Magnetic Resonance | Quantum Systems | Unitary OperationsError Accumulation |

This paper describes an effective method for extracting as much information as possible from pooling experiments for library screening. Pools are collections of clones, and screening a pool with a probe determines whether any of these clones are positive for the probe. The results of the pool screenings are interpreted, or decoded, to infer which clones are candidates to be positive. These candidate positives are subjected to confirmatory testing. Decoding the pool screening results is ...

Known for | Pooling Experiments | Library Screening | Markov Chain | Decoding AlgorithmPositive Clones |

### A study of quantum error correction by geometric algebra and liquid-state NMR spectroscopy

[ PUBLICATION ]

Quantum error correcting codes enable the information contained in a **quantum state** to be protected from decoherence due to external perturbations. Applied to NMR, this procedure does not alter normal relaxation, but rather converts the state of a 'data' spin into multiple quantum coherences involving additional ancilla spins. These multiple quantum coherences relax at differing rates, thus permitting the original state of the data to be approximately reconstructed by mixing them together ...

Known for | Geometric Algebra | Quantum Error Correction | State Nmr | Product Operator FormalismDecoherence Models |

### Quantum simulation of a three-body-interaction Hamiltonian on an NMR quantum computer

[ PUBLICATION ]

Extensions of average Hamiltonian theory to **quantum computation** permit the design of arbitrary Hamiltonians, allowing rotations throughout a large Hilbert space. In this way, the kinematics and dynamics of any quantum system may be simulated by a quantum computer. A basis mapping between the systems dictates the average Hamiltonian in the **quantum computer** needed to implement the desired Hamiltonian in the simulated system. The flexibility of the procedure is illustrated with NMR on 13C ...

Known for | Quantum Simulation | Average Hamiltonian | Threebody Interaction | Hilbert Space13c Labeled |

## Key People For **Probability Estimation**

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