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The predictive success of quantum mechanics underpins many areas of modern science, even as the exact simulation of large, interacting quantum systems remains beyond the reach of classical computation. This success has been enabled by the remarkable advancement of scalable numerical approximation methods, which often demonstrate practical accuracy despite the absence of formal guarantees. As…
Sometimes I encounter something I need to do and I think “I’m gonna need my big internet for this”, e.g. filing taxes, backing up documents, digging up some old file, etc. But these situations are becoming less frequent. I can do most things, if not everything, on my medium internet. I think the size of your daily internet plays an important role in how we integrate it into our…
I started leaving my phone at home, and I think you can too! I recently made some changes to how I interact with technology recently, and so far it’s been a positive experience. In this post, I will make the case for why you should consider leaving your phone at home as much as possible, and that the amount of times when this is feasible is potentially more than you might expect leaving your…
We can only assume that in the above product demonstration, the Cinco MIDI Organizer is being stretched to its computational limits, as Cinco has a large tech branch where they showcase new technologies . There are ~180 digits in the Cinco MIDI Organizer’s (CMO) UMRN (Unique Midi Routing Number). This means it can index as many as 10^180 MIDI files. That means if you filled up the CMO with…
The goal of benchmarking is to determine how far the output of a noisy system is from its ideal behavior; this becomes exceedingly difficult for large quantum systems where classical simulations become intractable. A common approach is to turn to circuits comprised of elements of the Clifford group (e.g., CZ, CNOT, π and π/2 gates), which probe quantum behavior but are nevertheless efficient to…
Instead of skipping ads, I would like to remove them altogether.
Quantum computing has emerged as a powerful computational paradigm capable of solving problems beyond the reach of classical computers. However, today’s quantum computers are noisy, posing challenges to obtaining accurate results. Here, we explore the impact of noise on quantum computing, focusing on the challenges in sampling bit strings from noisy quantum computers and the implications for…
Inspired by: On digital relationships, by Manu Around 2010 I met someone named Yineli on Last.fm through commenting on each others’ profiles. We had similar music tastes, and she introduced me to Blue Foundation and Portishead . Eventually we moved off talking on Last.fm, and decided to share MP3s in a shared DropBox folder. Once every month or so for about a year we would add some MP3s in a…
Lizards.com People used to use the internet to explore. I used to go on StumbleUpon for hours when I was little, or hop around different pages on Wikipedia . I think the desire to surf the web explains Depths of Wikipedia . When I was maybe six years old, we had a computer room that was a small nook that had a small window overlooking our back yard. It could have been an attic if it was unfinished…
I had a really strange experience when I got on the train a while back. Everyone was on their phone. I don’t mean most people were on their phones, I mean everyone was on their phone. I feel like writing about this at all is beating a dead horse because intuitively everyone seems to know that we’re not using phones in a healthy way. But damn, this seems like it’s getting really…
I made QR codes that are optimized for tattooing, and got one!
I’ve seen some people write about their journey learning to code. I thought I’d do the same for myself here. Childhood When I was growing up I had access to a computer from around age 6 I think? It was the family computer, some beige tower with a big CRT monitor. For a while it didn’t have internet access, but I loved poking around in the settings. Growing up I also had Legos,…
I’ve been deeply interested in the idea of digital identity lately. I’ve been experimenting with what this looks like for myself, and I’d like to capture some ideas I have about what this means more broadly. Consider two axes: digital vs material, and identity vs society. My claims are that (1) our current condition blurs each of these lines and (2) their connection is both…
I’m thinking about Digital Gardens and alternate forms of social networks lately. I’ve found a couple interesting places (be they blogs, digital gardens, or other digital spaces) I’ve found on the WWW : Gwern.net nLab Manu 32-Bit Café Notes ‒ Szymon Kaliski|Szymon Kaliski The Yesterweb The Missing Premise sadgrl.online Tom Critchlow the museum of alexandra The Intersect Robb…
The evolution of my homelab through the years.
Quantum error mitigation is a promising route to achieving quantum utility, and potentially quantum advantage in the near-term. Many state-of-the-art error mitigation schemes use knowledge of the errors in the quantum processor, which opens the question to what extent inaccuracy in the error model impacts the performance of error mitigation. In this work, we develop a methodology to efficiently…
Adaptive variational quantum simulation algorithms use information from a quantum computer to dynamically create optimal trial wave functions for a given problem Hamiltonian. A key ingredient in these algorithms is a predefined operator pool from which trial wave functions are constructed. Finding suitable pools is critical for the efficiency of the algorithm as the problem size increases. Here,…
Variational quantum eigensolvers (VQEs) represent a powerful class of hybrid quantum-classical algorithms for computing molecular energies. Various numerical issues exist for these methods, however, including barren plateaus and large numbers of local minima. In this work, we consider the Adaptive, Problem-Tailored Variational Quantum Eiegensolver (ADAPT-VQE) ansätze, and examine how they are…
We introduce a volumetric benchmark for near-term quantum platforms based on the generation and verification of genuine entanglement across n-qubits using graph states and direct stabilizer measurements. Our benchmark evaluates the robustness of multipartite and bipartite n-qubit entanglement with respect to many sources of hardware noise: qubit decoherence, CNOT and swap gate noise, and readout…
The quantum approximate optimization algorithm (QAOA) is a hybrid variational quantum-classical algorithm that solves combinatorial optimization problems. While there is evidence suggesting that the fixed form of the standard QAOA Ansatz is not optimal, there is no systematic approach for finding better Ansätze. We address this problem by developing an iterative version of QAOA that is problem…
The variational quantum eigensolver is currently the flagship algorithm for solving electronic structure problems on near-term quantum computers. The algorithm involves implementing a sequence of parameterized gates on quantum hardware to generate a target quantum state, and then measuring the molecular energy. Due to finite coherence times and gate errors, the number of gates that can be…
Several quantum many-body models in one dimension possess exact solutions via the Bethe ansatz method, which has been highly successful for understanding their behavior. Nevertheless, there remain physical properties of such models for which analytic results are unavailable and which are also not well described by approximate numerical methods. Preparing Bethe ansatz eigenstates directly on a…
One of the most promising applications of noisy intermediate-scale quantum computers is the simulation of molecular Hamiltonians using the variational quantum eigensolver (VQE). We show that encoding symmetries of the simulated Hamiltonian in the VQE ansatz reduces both classical and quantum resources compared to other widely available ansatze. Through simulations of the H2 molecule and of a…
Quantum chemistry is a key application area for noisy-intermediate scale quantum (NISQ) devices, and therefore serves as an important benchmark for current and future quantum computer performance. Previous benchmarks in this field have focused on variational methods for computing ground and excited states of various molecules, including a benchmarking suite focused on the performance of computing…
Quantum simulation, one of the most promising applications of a quantum computer, is currently being explored intensely using the variational quantum eigensolver. The feasibility and performance of this algorithm depend critically on the form of the wave-function ansatz. Recently in Ref. [Nat. Commun. 10, 3007 (2019)], an algorithm termed ADAPT-VQE was introduced to build system-adapted ansätze…
High-fidelity single- and two-qubit gates are essential building blocks for a fault-tolerant quantum computer. While there has been much progress in suppressing single-qubit gate errors in superconducting qubit systems, two-qubit gates still suffer from error rates that are orders of magnitude higher. One limiting factor is the residual ZZ-interaction, which originates from a coupling between…
Variational Quantum Algorithms (VQAs) are a promising application for near-term quantum processors, however the quality of their results is greatly limited by noise. For this reason, various error mitigation techniques have emerged to deal with noise that can be applied to these algorithms. Recent work introduced a technique for mitigating expectation values against correlated measurement errors…
Superconducting transmon qubits are of great interest for quantum computing and quantum simulation. A key component of quantum chemistry simulation algorithms is breaking up the evolution into small steps, which naturally leads to the need for nonmaximally entangling, arbitrary CPHASE gates. Here we design such microwave-based gates using an analytically solvable approach leading to smooth, simple…
The variational quantum eigensolver is one of the most promising approaches for performing chemistry simulations using noisy intermediate-scale quantum (NISQ) processors. The efficiency of this algorithm depends crucially on the ability to prepare multi-qubit trial states on the quantum processor that either include, or at least closely approximate, the actual energy eigenstates of the problem…
Implementing high-fidelity two-qubit gates in single-electron spin qubits in silicon double quantum dots is still a major challenge. In this work we employ analytical methods to design control pulses that generate high-fidelity entangling gates for quantum computers based on this platform. Using realistic parameters and initially assuming a noise-free environment, we present simple control pulses…
Me I like computers I live/work in NYC My cat’s name is Hoss Work Some of my professional background (all thoughts/ramblings/opinions my own): I did my undergrad in math and physics at the University of Georgia. Then I was an intern at Wolfram Research working on computational number theory. Then I did my PhD in physics (quantum computing) at Virginia Tech, where I was advised by Sophia…
Samantha V. Barron, PhD IBM Quantum, Software Developer samantha.wiki , LinkedIn , Google Scholar , GitHub , hello@samantha.wiki I currently work at IBM Quantum, where I develop and improve error mitigation and characterization techniques in the Qiskit Primitives . Previously, during my Ph.D. , I created entangling gates for superconducting qubits, improved variational algorithms, and analyzed…
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