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Cavity piezo-mechanics for superconducting-nanophotonic quantum interface
Hybrid quantum systems are essential for the realization of distributed quantum networks. In particular, piezo-mechanics operating at typical superconducting qubit frequencies features low thermal excitations, and offers an appealing platform to bridge superconducting quantum processors and optical telecommunication channels. However, integrating superconducting and optomechanical elements at cryogenic temperatures with sufficiently strong interactions remains a tremendous challenge. Here, we report an integrated superconducting cavity piezo-optomechanical platform where 10 GHz phonons are resonantly coupled with photons in a superconducting cavity and a nanophotonic cavity at the same time. Taking advantage of the large piezo-mechanical cooperativity (
C
em
~7) and the enhanced optomechanical coupling boosted by a pulsed optical pump, we demonstrate coherent interactions at cryogenic temperatures via the observation of efficient microwave-optical photon conversion. This hybrid interface makes a substantial step towards quantum communication at large scale, as well as novel explorations in microwave-optical photon entanglement and quantum sensing mediated by gigahertz phonons.
Hybrid quantum systems would allow interfacing superconducting nodes with optical links. Here, the authors demonstrate an integrated platform where 10 GHz phonons are resonantly coupled with photons in a superconducting cavity and a nanophotonic cavity at the same time, allowing efficient mediation of bidirectional microwave-optical conversion.
Journal Article
مراكش خلال عصر الموحدين : دراسة في الحياة الاجتماعية والاقتصادية
قد اعتمدت هذه الدراسة على جملة من المصادر، كان بعضها ذا فائدة كبيرة لا غنى عنها ولبعضها فائدة ثانوية، وقد تنوعت اتجاهات تلك المصادر فمنها (الجغرافية، والتاريخية، وكتب التراجم والطبقات) فضلا عن المراجع الحديثة، وهدف وهو تعريف الشباب العربي الواعي بجوانب مشرقة من سيرة أمتنا المجيدة من خلال تسليط الضوء على واحدة من المدن العربية المهمة ألا وهي مدينة مراكش الحمراء التي أصبحت مركز إشعاع حضاري بعد أقل من سبعين عاما على تأسيسها فأن أصبت فهو قصدي ومبتغاي وأن أخطأت فحسبي أن لي أجر المجتهد.
Book
Optical observation of single spins in silicon
The global quantum internet will require long-lived, telecommunications-band photon–matter interfaces manufactured at scale
1
. Preliminary quantum networks based on photon–matter interfaces that meet a subset of these demands are encouraging efforts to identify new high-performance alternatives
2
. Silicon is an ideal host for commercial-scale solid-state quantum technologies. It is already an advanced platform within the global integrated photonics and microelectronics industries, as well as host to record-setting long-lived spin qubits
3
. Despite the overwhelming potential of the silicon quantum platform, the optical detection of individually addressable photon–spin interfaces in silicon has remained elusive. In this work, we integrate individually addressable ‘T centre’ photon–spin qubits in silicon photonic structures and characterize their spin-dependent telecommunications-band optical transitions. These results unlock immediate opportunities to construct silicon-integrated, telecommunications-band quantum information networks.
Individually addressable ‘T centre’ photon-spin qubits are integrated in silicon photonic structures and their spin-dependent telecommunications-band optical transitions characterized, creating opportunities to construct silicon-integrated, telecommunications-band quantum information networks.
Journal Article
Resonant terahertz detection using graphene plasmons
Plasmons, collective oscillations of electron systems, can efficiently couple light and electric current, and thus can be used to create sub-wavelength photodetectors, radiation mixers, and on-chip spectrometers. Despite considerable effort, it has proven challenging to implement plasmonic devices operating at terahertz frequencies. The material capable to meet this challenge is graphene as it supports long-lived electrically tunable plasmons. Here we demonstrate plasmon-assisted resonant detection of terahertz radiation by antenna-coupled graphene transistors that act as both plasmonic Fabry-Perot cavities and rectifying elements. By varying the plasmon velocity using gate voltage, we tune our detectors between multiple resonant modes and exploit this functionality to measure plasmon wavelength and lifetime in bilayer graphene as well as to probe collective modes in its moiré minibands. Our devices offer a convenient tool for further plasmonic research that is often exceedingly difficult under non-ambient conditions (e.g. cryogenic temperatures) and promise a viable route for various photonic applications.
Plasmons confined in field effect transistors were long envisioned for resonant detection of light at THz frequencies, however realization of such photodetectors has proven challenging. Here, the authors fabricate antenna-coupled graphene transistors which exhibit resonant photoresponse to incident radiation and use them to study plasmons in graphene and its moiré superlattices.
Journal Article
تاريخ الغرب الإسلامي في عصر الموحدين
يتناول كتاب (تاريخ الغرب الإسلامي في عصر الموحدين) والذي قام بتأليفه (الأستاذ المساعد الدكتور محمد عبد الله عبد فزع المعموري) في حوالي (272) صفحة من القطع المتوسط موضوع (تاريخ المغرب العربي) مستعرضا المحتويات التالية : الفصل الأول بعنوان الغرب الإسلامي تحت حكم الناصر الموحدي، حياة الناصر الموحدي، اسمه ونسبه وألقابه وكناه، الفصل الثاني بعنوان التنظيمات الإدارية والعسكرية للغرب الإسلامي في عهد الناصر الموحدي، التنظيمات الإدارية.
Book
Measuring the knot of non-Hermitian degeneracies and non-commuting braids
Any system of coupled oscillators may be characterized by its spectrum of resonance frequencies (or eigenfrequencies), which can be tuned by varying the system’s parameters. The relationship between control parameters and the eigenfrequency spectrum is central to a range of applications
1
–
3
. However, fundamental aspects of this relationship remain poorly understood. For example, if the controls are varied along a path that returns to its starting point (that is, around a ‘loop’), the system’s spectrum must return to itself. In systems that are Hermitian (that is, lossless and reciprocal), this process is trivial and each resonance frequency returns to its original value. However, in non-Hermitian systems, where the eigenfrequencies are complex, the spectrum may return to itself in a topologically non-trivial manner, a phenomenon known as spectral flow. The spectral flow is determined by how the control loop encircles degeneracies, and this relationship is well understood for
N
=
2
(where
N
is the number of oscillators in the system)
4
,
5
. Here we extend this description to arbitrary
N
. We show that control loops generically produce braids of eigenfrequencies, and for
N
>
2
these braids form a non-Abelian group that reflects the non-trivial geometry of the space of degeneracies. We demonstrate these features experimentally for
N
=
3
using a cavity optomechanical system.
Control loops generically produce braids of eigenfrequencies, and these braids form a non-Abelian group that reflects the non-trivial geometry of the space of degeneracies; these features are demonstrated experimentally using a cavity optomechanical system.
Journal Article
Signatures of moiré-trapped valley excitons in MoSe2/WSe2 heterobilayers
The formation of moiré patterns in crystalline solids can be used to manipulate their electronic properties, which are fundamentally influenced by periodic potential landscapes. In two-dimensional materials, a moiré pattern with a superlattice potential can be formed by vertically stacking two layered materials with a twist and/or a difference in lattice constant. This approach has led to electronic phenomena including the fractal quantum Hall effect
1
–
3
, tunable Mott insulators
4
,
5
and unconventional superconductivity
6
. In addition, theory predicts that notable effects on optical excitations could result from a moiré potential in two-dimensional valley semiconductors
7
–
9
, but these signatures have not been detected experimentally. Here we report experimental evidence of interlayer valley excitons trapped in a moiré potential in molybdenum diselenide (MoSe
2
)/tungsten diselenide (WSe
2
) heterobilayers. At low temperatures, we observe photoluminescence close to the free interlayer exciton energy but with linewidths over one hundred times narrower (around 100 microelectronvolts). The emitter
g
-factors are homogeneous across the same sample and take only two values, −15.9 and 6.7, in samples with approximate twist angles of 60 degrees and 0 degrees, respectively. The
g
-factors match those of the free interlayer exciton, which is determined by one of two possible valley-pairing configurations. At twist angles of approximately 20 degrees the emitters become two orders of magnitude dimmer; however, they possess the same
g
-factor as the heterobilayer at a twist angle of approximately 60 degrees. This is consistent with the umklapp recombination of interlayer excitons near the commensurate 21.8-degree twist angle
7
. The emitters exhibit strong circular polarization of the same helicity for a given twist angle, which suggests that the trapping potential retains three-fold rotational symmetry. Together with a characteristic dependence on power and excitation energy, these results suggest that the origin of the observed effects is interlayer excitons trapped in a smooth moiré potential with inherited valley-contrasting physics. This work presents opportunities to control two-dimensional moiré optics through variation of the twist angle.
The trapping of interlayer valley excitons in a moiré potential formed by a molybdenum diselenide/tungsten diselenide heterobilayer with twist angle control is reported.
Journal Article