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

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

Seminar in Condensed Matter Physics presents "Symmetry and topology of quasiparticles and their bound states in correlated insulators"

Topic: 
Symmetry and topology of quasiparticles and their bound states in correlated insulators
Abstract / Description: 

In this talk, I explore two examples of how the symmetry of a microscopic lattice or topology of an underlying non-interacting band structure can be imprinted in the excitations of strongly-correlated insulators. First, I show that previously-unnoticed crystal symmetry constraints drastically alter the understanding of Ising quantum criticality in the quasi-1D magnetic insulator CoNb2O6, resolving decade-old puzzles related to the dispersion of confined 'kinks' in the ordered phase and the decay of spin-flip quasiparticles in the paramagnetic phase [1]. Turning next to the correlated quantum anomalous Hall insulator recently observed in twisted bilayer graphene near the magic angle, I show that this state supports stable, weakly-dispersing flat bands of neutral bosonic excitons with substantial Berry curvature [2], and argue that these can under certain conditions form a new hierarchy of bosonic fractional quantum Hall liquids [3].

References:
[1] M. Fava, R. Coldea, and S.A. Parameswaran, arXiv:2004.04169 (2020).
[2] Y.H. Kwan, Y. Hu, S.H. Simon, and S.A. Parameswaran, arXiv:2003.11560 (2020).
[3] Y.H. Kwan, Y. Hu, S.H. Simon, and S.A. Parameswaran, arXiv:2003.11559 (2020).

Date and Time: 
Thursday, May 7, 2020 - 12:00pm
Venue: 
Zoom (email vkhemani for link)

Stanford Institute for Theoretical Physics presents "Void formation in operator growth, quantum chaos and black hole evaporation"

Topic: 
Void formation in operator growth, quantum chaos and black hole evaporation
Abstract / Description: 

I first introduce the concept of void formation in Heisenberg evolution of operators and provide support that it can be used to distinguish chaotic and integrable systems.

After a brief discussion of applications of void formation to entanglement growths and generation of multi-partite entanglement, I will explain how it can provide insights into evolution of black holes by considering some simple quantum mechanical toy models of black hole evaporation.

Date and Time: 
Monday, May 4, 2020 - 2:00pm
Venue: 
Zoom id: 165-492-015

Stanford Institute for Theoretical Physics presents "Continuum Quantum Field Theories for Fractons"

Topic: 
Continuum Quantum Field Theories for Fractons
Abstract / Description: 

Starting with a lattice system at short distances, its long-distance behavior is captured by a continuum Quantum Field Theory (QFT). This description is universal, i.e. it is independent of most of the details of the microscopic system. Surprisingly, certain recently discovered lattice systems, and in particular models of fractons, seem to violate this general dogma. Motivated by this apparent contradiction, we will present exotic continuum QFTs that describe these systems.

Date and Time: 
Monday, April 27, 2020 - 2:00pm
Venue: 
Zoom ID: 165 492 015

Stanford Institute for Theoretical Physics presents "Replica wormhole and information retrieval in the SYK model coupled to Majorana chains"

Topic: 
Replica wormhole and information retrieval in the SYK model coupled to Majorana chains
Abstract / Description: 

Motivated by recent studies of the information paradox in (1+1)-D anti-de Sitter spacetime with a bath described by a (1+1)-D conformal field theory, we study the dynamics of second Rényi entropy of the Sachdev-Ye-Kitaev (SYK) model (χ) coupled to a Majorana chain bath (ψ). The system is prepared in the thermofield double (TFD) state and then evolved by HL+HR. For small system-bath coupling, we find that the second Rényi entropy S(2)χL,χR of the SYK model undergoes a first order transition during the evolution. In the sense of holographic duality, the long-time solution corresponds to a "replica wormhole". The transition time corresponds to the Page time of a black hole coupled to a thermal bath. We further study the information scrambling and retrieval by introducing a classical control bit, which controls whether or not we add a perturbation in the SYK system. The mutual information between the bath and the control bit shows a positive jump at the Page time, indicating that the entanglement wedge of the bath includes an island in the holographic bulk.

Date and Time: 
Monday, April 20, 2020 - 2:00pm
Venue: 
Zoom id: 165-492-015

Stanford Institute for Theoretical Physics presents "On the Entropy of an Einstein-Rosen Bridge"

Topic: 
On the Entropy of an Einstein-Rosen Bridge
Abstract / Description: 

We propose a new link between entropy and area: an eternal black hole with an ER bridge with cross-section A can carry quantum information, or be in a mixed state, with entropy S ≤ A/4GN . We provide evidence for our proposal in the context of AdS3 and JT gravity, by using the Island prescription and replica wormhole method for computing the Renyi entropy. We argue that a typical two sided black hole is described by a 'thermo-mixed double' state with only classical correlations between the two sides. Our reasoning suggests that an ER wormhole acts like a topological quantum memory, similar to the toric code.

Zoom id: 165-492-015 (Please note that this is a recurring id, valid till May 11.)

Date and Time: 
Monday, April 13, 2020 - 2:00pm
Venue: 
Zoom

QFarm Quantum Seminar Series presents "Generalized amplitude damping channel: The single greatest qubit mystery in quantum Shannon theory"

Topic: 
Generalized amplitude damping channel: The single greatest qubit mystery in quantum Shannon theory
Abstract / Description: 

The generalized amplitude damping channel (GADC) is one of the sources of noise in superconducting-circuit-based quantum computing. It can be viewed as the qubit analogue of the bosonic thermal channel, and it thus can be used to model lossy processes in the presence of background noise for low-temperature systems. In this work, we provide an information-theoretic study of the GADC. We first determine the parameter range for which the GADC is entanglement breaking and the range for which it is anti-degradable. We then establish several upper bounds on its classical, quantum, and private capacities. These bounds are based on data-processing inequalities and the uniform continuity of information-theoretic quantities, as well as other techniques. Our upper bounds on the quantum capacity of the GADC are tighter than the known upper bound reported recently in [Rosati et al., Nat. Commun. 9, 4339 (2018)] for the entire parameter range of the GADC, thus reducing the gap between the lower and upper bounds. We also establish upper bounds on the two-way assisted quantum and private capacities of the GADC. These bounds are based on the squashed entanglement, and they are established by constructing particular squashing channels. We compare these bounds with the max-Rains information bound, the mutual information bound, and another bound based on approximate covariance. For all capacities considered, we find that a large variety of techniques are useful in establishing bounds.

Joint work with Sumeet Khatri and Kunal Sharma

Date and Time: 
Wednesday, April 15, 2020 - 12:00pm
Venue: 
Zoom link: https://stanford.zoom.us/j/987676025

Stanford Institute for Theoretical Physics presents "Towards a 3d Ising model with a weakly-coupled string theory dual"

Topic: 
Towards a 3d Ising model with a weakly-coupled string theory dual
Abstract / Description: 

I'll discuss old and new motivations for a string theory description of the critical behavior of the 3d Ising model. Then I'll modify the Ising model so that the string theory is under better theoretical control, and describe the effects of this modification on the phase diagram. I'll conclude with some comments about the worldsheet theory.

Based on 2003.04349, with Nabil Iqbal.

Date and Time: 
Monday, April 6, 2020 - 2:00pm
Venue: 
Zoom id: 165-492-015

Pages

Subscribe to RSS - QFarm