東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

The C-shunt Flux Qubit: A New Genera...

Birenbaum, Jeffrey Scott.

Linked to FindBook

Google Book

Amazon

博客來

The C-shunt Flux Qubit: A New Generation of Superconducting Flux Qubit.

Record Type:	Electronic resources : Monograph/item
Title/Author:	The C-shunt Flux Qubit: A New Generation of Superconducting Flux Qubit./
Author:	Birenbaum, Jeffrey Scott.
Description:	161 p.
Notes:	Source: Dissertation Abstracts International, Volume: 76-08(E), Section: B.
Contained By:	Dissertation Abstracts International76-08B(E).
Subject:	Quantum physics. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3686192
ISBN:	9781321629408

The C-shunt Flux Qubit: A New Generation of Superconducting Flux Qubit.
Birenbaum, Jeffrey Scott.

The C-shunt Flux Qubit: A New Generation of Superconducting Flux Qubit. - 161 p.

Source: Dissertation Abstracts International, Volume: 76-08(E), Section: B.

Thesis (Ph.D.)--University of California, Berkeley, 2014.

While quantum computation has the potential to revolutionize the scientific community, to date no architecture has been developed which offers the necessary combination of high coherence times and massive scalability. Superconducting flux qubits satisfy the second requirement well but to date useful devices are limited to coherence times of typically only a few mus. In this dissertation we examine the possibilities of improving the coherence performance of the flux qubit to the levels required for fault-tolerant quantum computation. We find that coherence times for many devices are limited by photon-induced quasiparticles and mitigation of these quasiparticles increases coherence times by more than a factor of two. Beyond this, however, we find little improvement in flux qubit performance compared to prior results. Despite improved fabrication techniques and varied device designs we find flux qubit coherence times are still typically below 5 mus. Furthermore, wide device-to-device variations are observed which prevent effective scaling of the flux qubit to quantum information circuits.

ISBN: 9781321629408Subjects--Topical Terms:

726746
Quantum physics.

The C-shunt Flux Qubit: A New Generation of Superconducting Flux Qubit.
LDR:03667nmm a2200313 4500 001 2077402
005 20161114130308.5
008 170521s2014 ||||||||||||||||| ||eng d
020 $a 9781321629408
035 $a (MiAaPQ)AAI3686192
035 $a AAI3686192
040 $a MiAaPQ $c MiAaPQ
100 1 $a Birenbaum, Jeffrey Scott. $3 3192905
245 1 4 $a The C-shunt Flux Qubit: A New Generation of Superconducting Flux Qubit.
300 $a 161 p.
500 $a Source: Dissertation Abstracts International, Volume: 76-08(E), Section: B.
500 $a Adviser: John Clarke.
502 $a Thesis (Ph.D.)--University of California, Berkeley, 2014.
520 $a While quantum computation has the potential to revolutionize the scientific community, to date no architecture has been developed which offers the necessary combination of high coherence times and massive scalability. Superconducting flux qubits satisfy the second requirement well but to date useful devices are limited to coherence times of typically only a few mus. In this dissertation we examine the possibilities of improving the coherence performance of the flux qubit to the levels required for fault-tolerant quantum computation. We find that coherence times for many devices are limited by photon-induced quasiparticles and mitigation of these quasiparticles increases coherence times by more than a factor of two. Beyond this, however, we find little improvement in flux qubit performance compared to prior results. Despite improved fabrication techniques and varied device designs we find flux qubit coherence times are still typically below 5 mus. Furthermore, wide device-to-device variations are observed which prevent effective scaling of the flux qubit to quantum information circuits.
520 $a Based on the proposal by You, et al. we develop of a capacitively-shunted version of the flux qubit called the C-shunt flux qubit. With the addition of a capacitive shunt across the small junction of the flux qubit we are able to reduce the amplitude sensitivity to both charge and flux noise by more than a factor of three. The result is a predicted ten-fold enhancement in the coherence times compared to the unshunted flux qubit. At the same time we preserve much of the anharmonicity of the flux qubit resulting in a device with coherence times comparable to modern transmons but with a factor of four better anharmonicity and more flexible coupling configurations.
520 $a By using a high-quality MBE aluminum shunt process on an annealed sapphire substrate coupled with a more conventional electron-beam-evaporated aluminum Josephson junction process we fabricate hybrid C-shunt flux qubits. We also incorporate a new bridgeless junction technique which offers more robust and repeatable fabrication processing. This technique enables improved accuracy of the junction sizing, a trait which will become essential as we move to multi-qubit experiments. T1 and T2 times for these C-shunt devices reach in excess of 40 mus at degeneracy, achieving the predicted ten-fold improvement based on the reduced noise sensitivity. At the same time we see decreased device-to-device variation with typical T1 times exceeding 20--25 mus at all bias points. Combined with the high anharmonicity and standard planar fabrication techniques these coherence times make the C-shunt flux qubit a competitive candidate for fault-tolerant quantum computation.
590 $a School code: 0028.
650 4 $a Quantum physics. $3 726746
650 4 $a Low temperature physics. $3 3173917
650 4 $a Nanoscience. $3 587832
690 $a 0599
690 $a 0598
690 $a 0565
710 2 $a University of California, Berkeley. $b Physics. $3 1671059
773 0 $t Dissertation Abstracts International $g 76-08B(E).
790 $a 0028
791 $a Ph.D.
792 $a 2014
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3686192