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Wei KX, Magesan E, Lauer I, Srinivasan S, Bogorin DF, Carnevale S, Keefe GA, Kim Y, Klaus D, Landers W, Sundaresan N, Wang C, Zhang EJ, Steffen M, Dial OE, McKay DC, Kandala A. Hamiltonian Engineering with Multicolor Drives for Fast Entangling Gates and Quantum Crosstalk Cancellation. Phys Rev Lett 2022; 129:060501. [PMID: 36018659 DOI: 10.1103/physrevlett.129.060501] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
Quantum computers built with superconducting artificial atoms already stretch the limits of their classical counterparts. While the lowest energy states of these artificial atoms serve as the qubit basis, the higher levels are responsible for both a host of attractive gate schemes as well as generating undesired interactions. In particular, when coupling these atoms to generate entanglement, the higher levels cause shifts in the computational levels that lead to unwanted ZZ quantum crosstalk. Here, we present a novel technique to manipulate the energy levels and mitigate this crosstalk with simultaneous off-resonant drives on coupled qubits. This breaks a fundamental deadlock between qubit-qubit coupling and crosstalk. In a fixed-frequency transmon architecture with strong coupling and crosstalk cancellation, additional cross-resonance drives enable a 90 ns CNOT with a gate error of (0.19±0.02)%, while a second set of off-resonant drives enables a novel CZ gate. Furthermore, we show a definitive improvement in circuit performance with crosstalk cancellation over seven qubits, demonstrating the scalability of the technique. This Letter paves the way for superconducting hardware with faster gates and greatly improved multiqubit circuit fidelities.
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Affiliation(s)
- K X Wei
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - E Magesan
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - I Lauer
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - S Srinivasan
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - D F Bogorin
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - S Carnevale
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - G A Keefe
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - Y Kim
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - D Klaus
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - W Landers
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - N Sundaresan
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - C Wang
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - E J Zhang
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - M Steffen
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - O E Dial
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - D C McKay
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - A Kandala
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
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2
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Kandala A, Wei KX, Srinivasan S, Magesan E, Carnevale S, Keefe GA, Klaus D, Dial O, McKay DC. Demonstration of a High-Fidelity cnot Gate for Fixed-Frequency Transmons with Engineered ZZ Suppression. Phys Rev Lett 2021; 127:130501. [PMID: 34623861 DOI: 10.1103/physrevlett.127.130501] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 07/28/2021] [Indexed: 06/13/2023]
Abstract
Improving two-qubit gate performance and suppressing cross talk are major, but often competing, challenges to achieving scalable quantum computation. In particular, increasing the coupling to realize faster gates has been intrinsically linked to enhanced cross talk due to unwanted two-qubit terms in the Hamiltonian. Here, we demonstrate a novel coupling architecture for transmon qubits that circumvents the standard relationship between desired and undesired interaction rates. Using two fixed frequency coupling elements to tune the dressed level spacings, we demonstrate an intrinsic suppression of the static ZZ while maintaining large effective coupling rates. Our architecture reveals no observable degradation of qubit coherence (T_{1},T_{2}>100 μs) and, over a factor of 6 improvement in the ratio of desired to undesired coupling. Using the cross-resonance interaction, we demonstrate a 180 ns single-pulse controlled not (cnot) gate, and measure a cnot fidelity of 99.77(2)% from interleaved randomized benchmarking.
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Affiliation(s)
- A Kandala
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - K X Wei
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - S Srinivasan
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - E Magesan
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - S Carnevale
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - G A Keefe
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - D Klaus
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - O Dial
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - D C McKay
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
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3
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Ku J, Xu X, Brink M, McKay DC, Hertzberg JB, Ansari MH, Plourde BLT. Suppression of Unwanted ZZ Interactions in a Hybrid Two-Qubit System. Phys Rev Lett 2020; 125:200504. [PMID: 33258640 DOI: 10.1103/physrevlett.125.200504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 09/02/2020] [Indexed: 06/12/2023]
Abstract
Mitigating crosstalk errors, whether classical or quantum mechanical, is critically important for achieving high-fidelity entangling gates in multiqubit circuits. For weakly anharmonic superconducting qubits, unwanted ZZ interactions can be suppressed by combining qubits with opposite anharmonicity. We present experimental measurements and theoretical modeling of two-qubit gate error for gates based on the cross resonance interaction between a capacitively shunted flux qubit and a transmon, and demonstrate the elimination of the ZZ interaction.
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Affiliation(s)
- Jaseung Ku
- Department of Physics, Syracuse University, Syracuse, New York 13244, USA
| | - Xuexin Xu
- Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52428, Germany
- Jülich-Aachen Research Alliance (JARA), Fundamentals of Future Information Technologies, Jülich 52428, Germany
| | - Markus Brink
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - David C McKay
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - Jared B Hertzberg
- IBM Quantum, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - Mohammad H Ansari
- Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52428, Germany
- Jülich-Aachen Research Alliance (JARA), Fundamentals of Future Information Technologies, Jülich 52428, Germany
| | - B L T Plourde
- Department of Physics, Syracuse University, Syracuse, New York 13244, USA
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4
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Abstract
As quantum circuits increase in size, it is critical to establish scalable multiqubit fidelity metrics. Here we investigate, for the first time, three-qubit randomized benchmarking (RB) on a quantum device consisting of three fixed-frequency transmon qubits with pairwise microwave-activated interactions (cross-resonance). We measure a three-qubit error per Clifford of 0.106 for all-to-all gate connectivity and 0.207 for linear gate connectivity. Furthermore, by introducing mixed dimensionality simultaneous RB-simultaneous one- and two-qubit RB-we show that the three-qubit errors can be predicted from the one- and two-qubit errors. However, by introducing certain coherent errors to the gates, we can increase the three-qubit error to 0.302, an increase that is not predicted by a proportionate increase in the one- and two-qubit errors from simultaneous RB. This demonstrates the importance of multiqubit metrics, such as three-qubit RB, on evaluating overall device performance.
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Affiliation(s)
- David C McKay
- IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - Sarah Sheldon
- IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - John A Smolin
- IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - Jerry M Chow
- IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - Jay M Gambetta
- IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
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5
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Naik RK, Leung N, Chakram S, Groszkowski P, Lu Y, Earnest N, McKay DC, Koch J, Schuster DI. Publisher Correction: Random access quantum information processors using multimode circuit quantum electrodynamics. Nat Commun 2018; 9:172. [PMID: 29317635 PMCID: PMC5760722 DOI: 10.1038/s41467-017-02521-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
In the original version of this Article, the affiliation details for Peter Groszkowski and Jens Koch were incorrectly given as 'Department of Physics, University of Chicago, Chicago, IL, 60637, USA', instead of the correct 'Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA'. This has now been corrected in both the PDF and HTML versions of the Article.
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Affiliation(s)
- R K Naik
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA.
| | - N Leung
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA
| | - S Chakram
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA
| | - Peter Groszkowski
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois, 60208, USA
| | - Y Lu
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA
| | - N Earnest
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA
| | - D C McKay
- IBM T.J. Watson Research Center, Yorktown Heights, NY, 10598, USA
| | - Jens Koch
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois, 60208, USA
| | - D I Schuster
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA.
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6
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Naik RK, Leung N, Chakram S, Groszkowski P, Lu Y, Earnest N, McKay DC, Koch J, Schuster DI. Random access quantum information processors using multimode circuit quantum electrodynamics. Nat Commun 2017; 8:1904. [PMID: 29199271 PMCID: PMC5712528 DOI: 10.1038/s41467-017-02046-6] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 11/03/2017] [Indexed: 11/13/2022] Open
Abstract
Qubit connectivity is an important property of a quantum processor, with an ideal processor having random access—the ability of arbitrary qubit pairs to interact directly. This a challenge with superconducting circuits, as state-of-the-art architectures rely on only nearest-neighbor coupling. Here, we implement a random access superconducting quantum information processor, demonstrating universal operations on a nine-qubit memory, with a Josephson junction transmon circuit serving as the central processor. The quantum memory uses the eigenmodes of a linear array of coupled superconducting resonators. We selectively stimulate vacuum Rabi oscillations between the transmon and individual eigenmodes through parametric flux modulation of the transmon frequency. Utilizing these oscillations, we perform a universal set of quantum gates on 38 arbitrary pairs of modes and prepare multimode entangled states, all using only two control lines. We thus achieve hardware-efficient random access multi-qubit control in an architecture compatible with long-lived microwave cavity-based quantum memories. Despite their versatility, superconducting qubits such as transmons still have limited coherence times compared to resonators. Here, the authors show how to use a single transmon to implement universal one-qubit and two-qubit operations among nine qubits encoded in superconducting resonators’ eigenmodes.
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Affiliation(s)
- R K Naik
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA.
| | - N Leung
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA
| | - S Chakram
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA
| | - Peter Groszkowski
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA
| | - Y Lu
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA
| | - N Earnest
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA
| | - D C McKay
- IBM T.J. Watson Research Center, Yorktown Heights, NY, 10598, USA
| | - Jens Koch
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA
| | - D I Schuster
- The James Franck Institute and Department of Physics, University of Chicago, Chicago, IL, 60637, USA.
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McKay DC, Naik R, Reinhold P, Bishop LS, Schuster DI. High-contrast qubit interactions using multimode cavity QED. Phys Rev Lett 2015; 114:080501. [PMID: 25768741 DOI: 10.1103/physrevlett.114.080501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Indexed: 06/04/2023]
Abstract
We introduce a new multimode cavity QED architecture for superconducting circuits that can be used to implement photonic memories, more efficient Purcell filters, and quantum simulations of photonic materials. We show that qubit interactions mediated by multimode cavities can have exponentially improved contrast for two qubit gates without sacrificing gate speed. Using two qubits coupled via a three-mode cavity system we spectroscopically observe multimode strong couplings up to 102 MHz and demonstrate suppressed interactions off resonance of 10 kHz when the qubits are ≈600 MHz detuned from the cavity resonance. We study Landau-Zener transitions in our multimode systems and demonstrate quasiadiabatic loading of single photons into the multimode cavity in 25 ns. We introduce an adiabatic gate protocol to realize a controlled-Z gate between the qubits in 95 ns and create a Bell state with 94.7% fidelity. This corresponds to an on/off ratio (gate contrast) of 1000.
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Affiliation(s)
- David C McKay
- James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Ravi Naik
- James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Philip Reinhold
- James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Lev S Bishop
- Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - David I Schuster
- James Franck Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
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8
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Abstract
Using a 3D spin-dependent optical lattice, we study thermalization and energy exchange between two ultracold Bose gases, one of which is strongly correlated and bound to the lattice and another that is free from the lattice potential. Disruption of interspecies thermalization is revealed through measurements of condensate fraction after the lattice is superimposed on the parabolic confining potential. By selectively heating the lattice-bound species and measuring the rate of heat transfer to the free state, suppression of energy exchange is observed. Comparison with a Fermi's golden rule prediction confirms that this effect is caused by a dispersion mismatch that reduces the phase space available for elastic collisions. This result has critical implications for methods proposed to cool strongly correlated lattice gases.
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Affiliation(s)
- David C McKay
- Department of Physics, University of Illinois, 1110 West Green Street, Urbana, Illinois 61801, USA
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Widmalm SE, Brooks SL, Sano T, Upton LG, McKay DC. Limitation of the diagnostic value of MR images for diagnosing temporomandibular joint disorders. Dentomaxillofac Radiol 2006; 35:334-8. [PMID: 16940481 DOI: 10.1259/dmfr/23427399] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES Many studies have shown that MRI findings are reliable when experienced calibrated observers work as a group. The hypothesis was that MRI findings can be used as the gold standard also when evaluation is made by single expert observers. STUDY DESIGN Temporomandibular joint (TMJ) MRIs of 34 patients were evaluated independently by four reviewers with expert knowledge of radiology for the presence of 13 specified pathologic entities, as well as the quality of the images, on a 5-step scale from "Sure Yes" to "Sure No". Intraclass correlation coefficients were calculated to estimate the rating reliability of the examiners. A coefficient of at least 0.8 was deemed good, between 0.60 and 0.80 was deemed acceptable, and less than 0.60 was considered poor. Additionally, weighted kappa statistics were used for pair-wise comparisons across all four reviewers. RESULTS The hypothesis was not supported by the results. None of the 13 correlation coefficients for comparisons between single examiner evaluations of pathologic entities was good and 8 were poor. CONCLUSION A diagnosis of TMD based on MRI examination protocols made by a single examiner should not be accepted as a gold standard with regard to TMJ disorders.
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Affiliation(s)
- S E Widmalm
- Department of Biological and Material Science, University of Michigan School of Dentistry, Ann Arbor, MI 48109-1078, USA
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Abstract
It is of clinical interest to record the amplitudes of temporomandibular joint (TMJ) sounds. The aim was to test the hypothesis that sealing the meatus, when placing a microphone in the ear canal affects such recording by increasing the sound pressure level (SPL). Bilateral recordings of 249 TMJ clickings were made from three subjects, using sampling rates of 48 or 96 kHz and 24 bits A/D conversion, with and without the ear canals sealed by Silicone putty. The peak-to-peak equivalent sound pressure level (peSPL) was higher (P < 0.001) when the ear canal was sealed (range of mean differences was 8.3-24.9 dB peSPL). This means that the signal to noise ratio can be improved by sealing the meatus because the electronic noise level is not increased. Most important is that the dynamic range of the clicking sounds was 62 dB that is larger than the effective dynamic range of a 16 bits sound card. Future studies are needed to establish normative peSPL values. However, cards with at least 24 bits A/D conversion will be required, especially in patients with suspected disc displacement with reduction, where the difference in loudness between opening and closing clicking often is large.
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Affiliation(s)
- S E Widmalm
- Department of Biologic Sciences, School of Dentistry, University of Michigan, USA.
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11
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Abstract
There are conflicting opinions about the frequency range of temporomandibular joint (TMJ) sounds. Some authors claim that the upper limit is about 650 Hz. The aim was to test the hypothesis that TMJ sounds may contain frequencies well above 650 Hz but that significant amounts of their energy are lost if the vibrations are recorded using contact sensors and/or travel far through the head tissues. Time-frequency distributions of 172 TMJ clickings (three subjects) were compared between recordings with one microphone in the ear canal and a skin contact transducer above the clicking joint and between recordings from two microphones, one in each ear canal. The energy peaks of the clickings recorded with a microphone in the ear canal on the clicking side were often well above 650 Hz and always in a significantly higher area (range 117-1922 Hz, P < 0.05 or lower) than in recordings obtained with contact sensors (range 47-375 Hz) or in microphone recordings from the opposite ear canal (range 141-703 Hz). Future studies are required to establish normative frequency range values of TMJ sounds but need methods also capable of recording the high frequency vibrations.
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Affiliation(s)
- S E Widmalm
- Department of Biologic Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI, USA.
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12
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Abstract
Differential diagnosis depends in cases with disk displacement on accurate identification of sound source. Mistakes may occur when clicking from one temporomandibular joint (TMJ) is heard on both sides of the head at auscultation and neither examiner nor patient, is sure about side. The hypothesis was that the head tissues affect spectral characteristics of TMJ sounds and that differences due to different positioning of sensors can be used in localization of source. The aim was to compare bilateral electronic recordings of unilateral TMJ sounds to obtain and compare attenuation, phase shift and time delay. Recordings were made from 12 subjects with unilateral clicking. Small electret condenser microphones, bandwidth 40-20 000 Hz, were placed at the openings of the auditory canals and the sounds were recorded at a sampling rate of 48 000 Hz. The head tissues acted as a filter causing a frequency dependent attenuation and phase shift. There was a time difference between the ipsi- and the contra lateral recordings, the latter always having a longer delay time (range 0.2-1.2 ms, group mean 0.68 ms, s.d. 0.292 ms). In conclusion, spectral analysis of bilateral electronic TMJ sound recordings is of diagnostic value when bilateral clicking is heard at auscultation and can help to avoid diagnosing a silent joint as clicking.
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Affiliation(s)
- S E Widmalm
- Department of Biologic and Materials Sciences, School of, Dentistry, University of Michigan, USA.
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Abstract
To study mandibular motions with respect to time (kinematics) and the forces causing and resulting from these motions (kinetics), four subjects generated rapid depression and elevation of the mandible (displacement of 0.224 m; peak velocity of 0.237 m s(-1) during depression and 0.269 m s(-1) during elevation). The motion of depression (duration of 0.195 s; kinetic energy of 2.072 x 10(-3) J) could be divided into a phase of acceleration (2.742 m s(-2); +/- 0.28 gn) and a phase of deceleration (2.264 m s(-2); - 0.23 gn), and the terminal excess kinetic energy of depression was absorbed and dissipated by, primarily, the temporomandibular joint. Similarly, the ensuing motion of elevation (duration of 0.182 s; kinetic energy of 2.948 x 10(-3) J) could be divided into a phase of acceleration (3.498 m s(-2); + 0.36 gn) and a phase of deceleration (2.931 m s(-2); -0.30 gn), and the terminal excess kinetic energy of elevation was absorbed and dissipated by, primarily, the dentitions and, secondarily, by the temporomandibular joint. Rapid depression of the mandible appeared to be under the central control of a preprogrammed motor command, and ensuing rapid elevation of the mandible appeared to be under the peripheral control of a segmental and/or transcortical reflex. During rapid depression and elevation of the mandible, the anterior suprahyoid, anterior temporalis, and sternocleidomastoid muscles were myoelectrically active 56%, 73%, and 71% of the time, respectively, and myomechanically active 42%, 59%, and 57% of the time, respectively. Over a follow-up period of 12 months, the studied mandibular motions did not cause injury to the dentitions and temporomandibular joint.
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Abstract
Following an introduction to the functional properties of a three-dimensional instantaneous helical axis pertaining to circular (rotatory) and linear (translatory) motions of the mandible, this feasibility study applied the concept of a mandibular average finite helical axis to the maneuver of cyclic opening and closing of the mouth in three healthy subjects. Through the accelerations and decelerations of a mandibular incisor point (instead of a mandibular condylar point) as well as the laws of physics, the kinetic reaction forces and reaction pressures in the upper and lower cavities of the temporomandibular joint (TMJ) were estimated over opening-closing distances of five and ten mm from centric occlusion. The translatory reaction pressures in the upper TMJ cavity (17-29 mm Hg) exceeded the rotatory reaction pressures in the lower TMJ cavity (5-12 mm Hg). The estimated reaction pressures were in close agreement with synovial fluid pressures measured in vivo in the TMJ of humans and pigs, and the biologic significance of frequent and/or prolonged increased TMJ hydrostatic pressures is discussed.
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Abstract
Albeit never substantiated through experimental and clinical evidence, the theoretical linchpin of the mechanics of a so-called whiplash injury of the temporomandibular joint (TMJ) is the postulate that a pre-existing depressor force (continual anchoring force), generated by the anterior suprahyoid (SH) muscles, will always act on the mandible and cause traumatic mouth opening (anterior acceleration of the TMJ condyles) when the neck is extended (posterior acceleration of the head). To test aspects of this postulate, six subjects assumed the positions of neutral (0 degrees ), medium (32 degrees ) and maximum (58 degrees ) neck extension while the mandible was in its postural positions of rest and light centric occlusion. By means of surface electromyography, it was shown that the relative contractile activities of the anterior SH muscles never exceeded 7.3% of the contractile activity required to anchor the mandible in a position of maximum depression. By means of electrognathography, it was shown that the maxillary and mandibular incisors were never separated by more than 2.6 mm during neutral, medium, and maximum extension of the neck. In other words, during neck extensions there was no evidence of a continual or induced voluntary or involuntary depressor force that would and could anchor the mandible in a position of traumatic mouth opening. Accordingly, and in agreement with other biophysical and biomedical evidence, it was concluded that there is no foundation for the pseudoscientific speculations and unsubstantiated opinions offered in support of a concept and diagnosis of a so-called TMJ whiplash injury. Additionally, this study found co-activation of cervical flexor muscles and mandibular elevator as well as depressor muscles.
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Abstract
Referring to the temporomandibular joint (TMJ) of the human mandibular locomotor system, it has been asserted that displacement of the TMJ disc and inflammation of TMJ tissues are the results of acute and indirect trauma to the TMJ; on occasion this is allegedly experienced in motor vehicle accidents and commonly known as a TMJ whiplash injury. It is postulated that the TMJ whiplash injury is released in the occupant or occupants of a target vehicle when its rear end is impacted by the front end of a bullet vehicle. On the basis of detailed analyses of TMJ trauma/pain histories and TMJ magnetic resonance images, presented as circumstantial evidence in favour of the postulated TMJ whiplash injury, and detailed analyses of the mathematical biophysics of the mandibular locomotor system as well as direct experimental evidence, it is concluded that the postulated TMJ whiplash injury does not exist as a single and independent disease entity caused by motor vehicle accidents. If TMJ disc displacement and inflammation are present, they are expressions of an insidious and progressive pre-existing (pre-accident) disease entity that is comprised of TMJ synovitis/osteoarthritis (phase of inflammation with presence of immune system cells), TMJ internal derangement (phase of disc displacement and deformation with presence of proteinases), and TMJ osteoarthrosis (phase of degeneration with absence of immune system cells). For the asserted TMJ whiplash manoeuvre and ensuing injury to occur as postulated, the laws of physics and biology would have to be suspended.
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17
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Abstract
Because a so-called mandibular whiplash injury requires the absence of short-latency jaw-closing reflexes in order to explain the postulated mechanism of injury (excessive jaw opening); the authors studied the presence and absence and more importantly, the kinematics (duration, displacement, velocity, acceleration) of monosynaptic and possibly, polysynaptic myotatic (stretch) reflexes in the jaw elevator muscles. In six healthy adults jaw jerk maneuvers were elicited through a brisk tap on the chin, and surface electromyography identified elevator reflexes while translational electrognathography identified the kinematics of the reflexes. The maneuvers were done while maintaining the rest position (3% MVC) and moderate clenching of the teeth (30% MVC). Electromyography was also used to identify phasic elevator excitations during a passive brisk neck extension maneuver. A sudden and unexpected elongation of the jaw elevators released autogenic reflex responses that, in conjunction with augmented tissue elasticity (stiffness), elevated the mandible into centric occlusion within approximately 150 milliseconds. In 86% of trials, the responses occurred regardless of the prevailing resting and clenching contractile activities. There was no evidence of a depressor force that consistently would and could anchor the mandible in a position of extreme or moderate depression, the theoretical linchpin of the mandibular whiplash injury. It was concluded that the mandibular locomotor system is very efficient in maintaining the rest and intercuspal positions of the mandible. This study found no evidence corroborating the mechanism claimed to release a so-called mandibular whiplash injury.
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Aabakken L, Chittom P, McKay DC, Uflacker R, Wilson FA. Percutaneous drainage of a mediastinal pancreatic pseudocyst: a paraspinal, extrapleural CT-guided approach. J Vasc Interv Radiol 1997; 8:283-5. [PMID: 9083998 DOI: 10.1016/s1051-0443(97)70556-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- L Aabakken
- Department of Medicine, Medical University of South Carolina, Charleston 29245, USA
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Houck WV, O'Brien PH, McKay DC, Uflacker R. Angiographic salvage of a malpositioned Hickman catheter: a cost-effective tool. Surgery 1997; 121:234-6. [PMID: 9037241 DOI: 10.1016/s0039-6060(97)90300-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Abstract
Using the mouth as an "in vivo articulator," the bilateral nonmasticatory ("empty") contact patterns of opposing cuspid and first molar teeth were determined in two healthy subjects with well-defined cuspid function and two healthy subjects with well-defined group function. The electronically recorded "empty" contact patterns pertained to the static intercuspal position and dynamic laterotrusion to the right and the left. On the basis of the "empty" tooth contact patterns and the number of electronically recorded masticatory cycles of one masticatory sequence, we postulated two simple models that attempted to predict the masticatory ("functional") tooth contacts of one sequence of unilateral mastication of apple and banana. Statistical comparisons between the predictions of the two models and the actual ("functional") contacts of in vivo mastication showed that the models predicted fairly well the observed tooth contacts on the nonchewing-side of the mouth, but not the observed tooth contacts on the chewing-side of the mouth. In consequence, "empty" (nonmasticatory) tooth contact patterns should not be equated with "functional" (masticatory) tooth contact patterns.
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Abstract
In 46 non-patients and 46 patients, the authors examined the presence (+) and absence (-) of canine tooth guidance (CG), i.e. dynamic dental articulation events in contrast to static dental occlusion events. During a right and a left laterotrusion of the mandible, the number of simple, mutually exclusive and exhaustive tooth guidance events (possibilities) was four. In addition, the authors examined the associations between temporomandibular joint (TMJ) sounds and canine guidance events. In non-patients, CG+ was relatively infrequent (30%), and CG- was relatively frequent (70%). In patients, CG+ was relatively infrequent (22%), and CG- was relatively frequent (78%). In both non-patients and patients, bilateral CG+ was rather infrequent (15%). In both non-patients and patients with the presence of TMJ sounds, CG+ was relatively infrequent (38%) while CG- was relatively frequent (61%). In non-patients as well as patients, no evidence was found that distal CG+ (putative lateral retrusive guidance) was associated with ipsilateral TMJ sounds (relative risk = 0%), nor that the association between mesial CG+ (putative lateral protrusive guidance) and ipsilateral TMJ sounds was beyond that of mere chance (relative risk = 50%).
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Affiliation(s)
- S J Donegan
- Marquette University, School of Dentistry, Milwaukee, Wisconsin, USA
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Abstract
In 46 non-patients and 46 patients, the authors examined the presence (+) and the absence (-) of laterotrusive (LG) and mediotrusive (MG) tooth guidance, i.e. dynamic dental articulation events in contrast to static dental occlusion events. During a right and left laterotrusion/mediotrusion of the mandible, the number of compound, mutually exclusive and exhaustive tooth guidance events (possibilities) was six. In addition, the presence and the absence of temporomandibular joint (TMJ) sounds, provoked TMJ pains, and the associations between TMJ sounds and tooth guidance events were examined. In non-patients, LG+ and MG+ was relatively infrequent (30%) while LG+ and MG- was relatively frequent (70%). In patients, LG+ and MG+ was relatively frequent (58%) while LG+ and MG- was relatively infrequent (42%). LG- and MG+ was absent in non-patients and rare in patients (3%). Either unilateral or bilateral MG+ was relatively infrequent in non-patients (30%) and relatively frequent in patients (59%). Bilateral MG+ was relatively infrequent in non-patients (20%) and relatively frequent in patients (52%). Either unilateral or bilateral TMJ sounds were relatively infrequent in non-patients (39%) and relatively frequent in patients (74%). Either unilateral or bilateral provoked TMJ pains were absent in non-patients and relatively frequent in patients (72%). The authors found no evidence that TMJ sounds were associated with the ipsilateral absence of so-called balancing contacts (MG-) in non-patients and patients. Finally, no evidence supporting the use of a so-called positive predictive value, and "extension concept' of probability theory was found.
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Affiliation(s)
- L V Christensen
- Marquette University, School of Dentistry, Milwaukee, Wisconsin, USA
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Christensen LV, McKay DC. TMD diagnostic decision-making and probability theory. Part II. Cranio 1996; 14:312-9. [PMID: 9110626 DOI: 10.1080/08869634.1996.11745983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
As it specifically pertains to temporomandibular disorders (TMD), this article is an educational analysis and discussion of some recently proposed diagnostic criteria, diagnostic methods, and diagnostic decision processes. On the basis of a discussion of classic probability theory, classic measurement theory, and examples using nonparametric inferential statistical tests, it is suggested that certain TMD diagnostic criteria and methods, and their associated decision matrix, favor subjective clinical opinions (largely pseudoscientific observations) and arbitrary clinical indices rather than objective scientific facts.
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Christensen LV, McKay DC. TMD diagnostic decision-making and probability theory. Part I. Cranio 1996; 14:240-8. [PMID: 9110616 DOI: 10.1080/08869634.1996.11745974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
This article is an educational analysis and discussion of some recently proposed diagnostic criteria, diagnostic methods, and diagnostic decision processes, pertaining specifically to temporomandibular disorders (TMD). On the basis of a discussion of classic probability theory, classic measurement theory, and examples using nonparametric inferential statistical tests, it is suggested that certain TMD diagnostic criteria and methods, and their associated decision matrix, favor subjective clinical opinions (largely pseudoscientific observations) and arbitrary clinical indices rather than objective scientific facts.
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Christensen LV, McKay DC. Biologic vs. psychologic dentistry. Cranio 1995; 13:69-71. [PMID: 8697502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Ellis JH, McKay DC, Sonda LP. Infusion of air into the collecting system to avoid needle blockage during percutaneous nephrostomy after extracorporeal shock-wave lithotripsy. AJR Am J Roentgenol 1992; 158:807-8. [PMID: 1546596 DOI: 10.2214/ajr.158.4.1546596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- J H Ellis
- Department of Radiology, University of Michigan Medical Center, Ann Arbor 48109-0330
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Abstract
In a sample of 20 non-patients, 60% of the subjects had an absence of subjective temporomandibular joint (TMJ) complaints (noises/sounds) that agreed with objective joint vibration analyses (electrovibratography). Among the remaining 40% of subjects, only 50% of the examined joints showed agreement between subjective and objective findings. Subjects appeared to be unable to reliably detect "weak" (early) symptoms of TMJ dysfunction but were able to reliably detect "strong" (late) symptoms of TMJ dysfunction and possibly disease. As measured through active protrusion and laterotrusion of the mandible, the guidance angles of the anterior teeth could not explain the absence and presence of TMJ vibrations.
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