EE Student Information

The Department of Electrical Engineering supports Black Lives Matter. Read more.

• • • • •

EE Student Information, Spring Quarter through Academic Year 2020-2021: FAQs and Updated EE Course List.

Updates will be posted on this page, as well as emailed to the EE student mail list.

Please see Stanford University Health Alerts for course and travel updates.

As always, use your best judgement and consider your own and others' well-being at all times.

QFarm

QFarm Quantum Seminar Series

Q-FARM presents "Scaling-up single-photon quantum hardware towards quantum-information processing with a quantum advantage"

Topic: 
Scaling-up single-photon quantum hardware towards quantum-information processing with a quantum advantage
Abstract / Description: 

Semiconductor quantum dots embedded in photonic nanostructures offer a highly efficient and coherent deterministic photon-emitter interface [1]. It constitutes an on-demand single-photon source for quantum-information applications, enables single-photon nonlinear, optics and the constructing of deterministic quantum gates for photons [2]. We review recent experimental progress, and demonstrate that the current technology can be scaled up to reach quantum advantage [3] with the demonstration of near-transform-limited emitters in high-cooperativity planar nanophotonic waveguides [4]. The coherent control of a single spin in the quantum dot [5, 6] offers additional opportunities of generating advanced multi-photon entangled states [7]. We finally discuss how this emergent hardware may be applied in a resource-efficient manner, e.g., for constructing a one-way quantum repeater [8].

References

[1] Lodahl et al., Rev. Mod. Phys. 87, 347 (2015).
[2] Lodahl, Quantum Science and Technology 3, 013001 (2018).
[3] Uppu et al., Arxiv: 2003.08919.
[4] Pedersen et al., ACS Photonics (2020).
[5] Javadi et al., Nature Nanotechnology 13, 398 (2018).
[6] Appel et al., Arxiv: 2006.15422.
[7] Tiurev et al., Arxiv: 2007.09295.
[8] Borregaard et al., Phys. Rev. X 10, 021071 (2020).

Date and Time: 
Wednesday, September 23, 2020 - 12:00pm
Venue: 
Zoom meeting ID: 987 676 025; password required.

Q-FARM presents "Demonstrating different advantages in quantum processing"

Topic: 
Demonstrating different advantages in quantum processing
Abstract / Description: 

Quantum computing famously promises an exponential speedup in runtime for universal computation applications such as code breaking and simulation. However, it is possible to identify a number of processing tasks—perhaps of a different nature—for which other quantum advantages exist. I'll give an overview of three such tasks: a memory advantage in stochastic simulation; a communication advantage in distributed processing; and a resource advantage in transforming probability distributions. I'll describe the photonic experimental realisation of one or two of these.

Date and Time: 
Wednesday, September 16, 2020 - 3:00pm
Venue: 
Zoom Meeting ID: 987 676 025; +Password

Q-FARM Quantum Seminar Series presents "Restrictions on logical gates in quantum error correction"

Topic: 
Restrictions on logical gates in quantum error correction
Abstract / Description: 

The disjointness for stabilizer codes in quantum error correction is an algebraic quantity tied to the structure of the stabilizer generators of a code. It can be used to characterize the properties of different classes of logical gates, placing bounds on the level of the Clifford hierarchy attainable by constant depth circuits. This talk will introduce the notion of disjointness, highlight its usefulness with several examples, and posit open questions for which the disjointness may be useful in addressing.

Date and Time: 
Wednesday, September 2, 2020 - 12:00pm
Venue: 
Zoom ID: 987 676 025; +password

Q-FARM presents "Free-Electron Quantum Optics"

Topic: 
Free-Electron Quantum Optics
Abstract / Description: 

Research of cavity quantum electrodynamics (CQED) has enabled new capabilities in quantum optics, quantum computation, and various quantum technologies. So far, all the work in this field has included light interacting with bound-electron systems such as atoms, quantum dots, and quantum circuits. In contrast, free-electron systems enable fundamentally different physical phenomena, as their energy distribution is continuous and not discrete, and allow for tunable transitions and selection rules.

We have developed a platform for studying free-electron CQED at the nanoscale and demonstrated it by observing coherent electron interaction with a photonic cavity for the first time. Our platform includes femtosecond lasers in an ultrafast transmission electron microscope, which created what is, in many respects, the most powerful nearfield optical microscope in the world today. We resolve photonic bandstructures as a function of energy, momentum, and polarization, simultaneously with capturing the spatial distribution of the photonic modes at deep-subwavelength resolution.

These capabilities open new paths toward using free electrons as carriers of quantum information. As examples, we show how to create free-electron qubits and implement quantum gates with femtosecond lasers. We further show how to measure quantum decoherence in space and time using the free-electron quantum interactions. Such interactions also enable new avenues for tunable X-ray sources, as we demonstrate with theory and experiments.

Date and Time: 
Wednesday, August 19, 2020 - 10:00am
Venue: 
Meeting ID: 987 676 025 (+ password)

Q-FARM presents "Large-Scale Quantum Photonic Processors"

Topic: 
Large-Scale Quantum Photonic Processors
Abstract / Description: 

Photons play a central role in many areas of quantum information science, either as qubit themselves or to mediate interactions between long-lived matter based qubits. Techniques for (1) high-fidelity generation, (2) precise manipulation and (3) ultra-efficient detection of quantum states of light are therefore a prerequisite for virtually all quantum technologies. A quantum photonic processor is the union of these three core technologies into a single system, and, bolstered by advances in integrated photonics, promises to be a versatile platform for quantum information science and beyond. In this talk I present recent progress towards large-scale quantum photonic processors and demonstrate how such systems enable new applications at the nexus of quantum mechanics and machine learning.

Date and Time: 
Wednesday, August 5, 2020 - 12:00pm
Venue: 
ZOOM ID: 987 676 025

Q-FARM presents "Quantum Metrology in the Era of Quantum Information"

Topic: 
Quantum Metrology in the Era of Quantum Information
Abstract / Description: 

I will review the most recent advances in the theoretical methods of quantum metrology, focusing on the quantum information related concepts such as quantum error-correction and matrix product states formalism. The aim of the talk is to show how the two fields, quantum metrology and quantum information, are closely connected and how they can benefit from each other. The talk will be based on three papers:

[1] R. Demkowicz-Dobrzanski, J. Czajkowski, P. Sekatski, Adaptive quantum metrology under general Markovian noise, Phys. Rev. X 7, 041009 (2017)

[2] K. Chabuda, J. Dziarmaga, T. J. Osborne, R.Demkowicz-Dobrzanski, Tensor-Network Approach for Quantum Metrology in Many-Body Quantum Systems, Nat. Commun. 11, 250 (2020)

[3] A. Kubica, R. Demkowicz-Dobrzanski, Using Quantum Metrological Bounds in Quantum Error Correction: A Simple Proof of the Approximate Eastin-Knill Theorem, arXiv:2004.11893 (2020)

 

Password via qfarm-contact@stanford.edu

Date and Time: 
Wednesday, July 22, 2020 - 10:00am
Venue: 
Meeting ID: 987 676 025; + password)

Q-FARM presents "Quantum Multiplexing: It's about time"

Topic: 
Quantum Multiplexing: It's about time
Abstract / Description: 

Despite their many applications over the last decades, entangled and single-photon sources from probabilistic sources such as spontaneous parametric downconversion have limited performance due to the presence of unwanted multi-pair events. For example, it is not possible to produce a heralded single photon with a probability exceeding 25%. However, by incorporating low-loss multiplexing (in our case, time-bin multiplexing), one can greatly enhance device performance. We will review our recent work in this area, and speculate about the future.

Date and Time: 
Wednesday, June 24, 2020 - 12:00pm
Venue: 
Zoom

Q-FARM presents "Many-body invariants from statistical correlations of randomized measurements"

Topic: 
Many-body invariants from statistical correlations of randomized measurements
Abstract / Description: 

With the advances of quantum simulators in implementing various quantum many-body states, it is important to find efficient ways to characterize and measure many-body states, without resorting to full quantum state tomography. Specifically, in contrast to electronic materials, where the measurements are mainly within the linear-response paradigm, quantum simulators offer unique access to the full wave function that inspires novel probing approaches. In this talk, I discuss how various quantities, such as entanglement spectrum, symmetry-protected topological invariants, and fractional many-body Chern number could be extracted. In the latter case, we show how such an invariant can be measured, using a single wave function, without the knowledge of the Hamiltonian. This should be contrasted to the conventional way, where on requires a family of many-body wave functions parameterized by twist angles in order to calculate the Berry curvature.

Science Advance 6, 3666 (2020)
arxiv 2005.13543
arxiv 2005.13677

Date and Time: 
Wednesday, June 17, 2020 - 12:00pm
Venue: 
Zoom ID: 987 676 025

QFARM Quantum Seminar Series presents "Robust Quantum Information Processing with Bosonic Modes"

Topic: 
Robust Quantum Information Processing with Bosonic Modes
Abstract / Description: 

Bosonic modes are widely used for quantum communication and information processing. Recent developments in superconducting circuits enable us to control bosonic microwave cavity modes and implement arbitrary operations allowed by quantum mechanics, such as quantum error correction against excitation loss errors. We investigate various bosonic codes, error correction schemes, and potential applications.

Date and Time: 
Wednesday, May 27, 2020 - 12:00pm
Venue: 
Zoom ID: 987 676 025

Q-FARM presents "Topological error correction in linear optical quantum computing"

Topic: 
Topological error correction in linear optical quantum computing
Abstract / Description: 

In linear optical quantum computing qubits do not fundamentally interact, and yet via measurement complex entanglement can be constructed to implement quantum error corrected computation via topological codes. As a hardware platform for quantum computation linear optics offers unique flexibility in the options for building up topological error correcting schemes. Some interesting examples are the long range connectivity which is straightforward in a photonic architecture, and the ability to move qubits around in temporal as well as spatial dimensions. I will give an overview of quantum computing with silicon photonics and demonstrate how these physical features of the photonic approach can inspire novel schemes for fault tolerance.

Date and Time: 
Monday, May 11, 2020 - 11:05am to 12:05pm
Venue: 
Zoom id: 987-676-025

Pages

Subscribe to RSS - QFarm