DIGITAL ACCESS TO

Scholarship at Harvard

WHAT IS DASH?

DASH is the central, open-access institutional repository of research by members of the Harvard community. Harvard Library Open Scholarship and Research Data Services (OSRDS) operates DASH to provide the broadest possible access to Harvard's scholarship. This repository hosts a wide range of Harvard-affiliated scholarly works, including pre- and post-refereed journal articles, conference proceedings, theses and dissertations, working papers, and reports.

More about DASH
 

Recent Submissions

No Thumbnail Available
Publication
No Thumbnail Available
Publication
Investment Feminism and Women's Health
(2024) DiMarco, Marina; Higgins, Abigail; Richardson, Sarah; Bruch, Joseph Dov; Marsella, Jamie
This essay introduces the term investment feminism to characterize the phenomenon in which financial actors position investment as a powerful lever for advancing gender equity. We offer investment feminism as an analytic tool that illuminates patterns and relations incompletely revealed by existing concepts such as commodity feminism and neoliberal feminism. We develop the concept of investment feminism through a close analysis of its role in the femtech industry, which markets technology and products to promote women's health. Drawing on industry reports, press coverage, and marketing materials, we describe how venture capital firms and femtech startups proffer financial investment as a high-impact means of feminist political action. We argue that while technology has the potential to yield services, tools, diagnostics, and therapies that benefit women, the technological solutions promoted by investment feminism within the women’s health space favor individual self-maintenance rather than structural change. We offer the concept of investment feminism as an analytic tool to support feminist scholars and activists in attending to the role of the financial sector and its ever-increasing influence on gender relations and feminist movements.
No Thumbnail Available
Publication
No Thumbnail Available
Publication
On the Computational Power of QAC0 with Barely Superlinear Ancillae
(2024-10-09) Anshu, Anurag; Dong, Yangjing; Ou, Fenging; Yao, Penghui
QAC0 is the family of constant-depth polynomial-size quantum circuits consisting of arbitrary single qubit unitaries and multi-qubit Toffoli gates. It was introduced by Moore [arXiv: 9903046] as a quantum counterpart of AC0, along with the conjecture that QAC0 circuits can not compute PARITY. In this work we make progress on this longstanding conjecture: we show that any depth-d QAC0 circuit requires n1+3−d ancillae to compute a function with approximate degree Θ(n), which includes PARITY, MAJORITY and MODk. We further establish superlinear lower bounds on quantum state synthesis and quantum channel synthesis. This is the first superlinear lower bound on the super-linear sized QAC0. Regarding PARITY, we show that any further improvement on the size of ancillae to n1+exp(−o(d)) would imply that PARITY ∉ QAC0. These lower bounds are derived by giving low-degree approximations to QAC0 circuits. We show that a depth-d QAC0 circuit with a ancillae, when applied to low-degree operators, has a degree (n+a)1−3−d polynomial approximation in the spectral norm. This implies that the class QLC0, corresponding to linear size QAC0 circuits, has approximate degree o(n). This is a quantum generalization of the result that LC0 circuits have approximate degree o(n) by Bun, Robin, and Thaler [SODA 2019]. Our result also implies that QLC0≠NC1.
No Thumbnail Available
Publication
UniqueQMA vs QMA: oracle separation and eigenstate thermalization hypothesis
(2024-10-31) Anshu, Anurag; Haferkamp, Jonas; Hwang, Yeongwoo; Nguyen, Quynh T.
We study the long-standing open question of the power of unique witness in quantum protocols, which asks if UniqueQMA, a variant of QMA whose accepting witness space is 1-dimensional, is equal to QMA. We show a quantum oracle separation between UniqueQMA and QMA via an extension of the Aaronson-Kuperberg's QCMA vs QMA oracle separation. In particular, we show that any UniqueQMA protocol must make Ω(D−−√) queries to a subspace phase oracle of unknown dimension ≤D to "find" the subspace. This presents an obstacle to relativizing techniques in resolving this question (unlike its classical analogue - the Valiant-Vazirani theorem - which is essentially a black-box reduction) and suggests the need to study the structure of the ground space of local Hamiltonians in distilling a potential unique witness. Our techniques also yield a quantum oracle separation between QXC, the class characterizing quantum approximate counting, and QMA. Very few structural properties are known that place the complexity of local Hamiltonians in UniqueQMA. We expand this set of properties by showing that the ground energy of local Hamiltonians that satisfy the eigenstate thermalization hypothesis (ETH) can be estimated through a UniqueQMA protocol. Specifically, our protocol can be viewed as a quantum expander test in a low energy subspace of the Hamiltonian and verifies a unique entangled state in two copies of the subspace. This allows us to conclude that if UniqueQMA ≠ QMA, then QMA-hard Hamiltonians must violate ETH under adversarial perturbations (more accurately, under the quantum PCP conjecture if ETH only applies to extensive energy subspaces). Our results serve as evidence that chaotic local Hamiltonians, such as the SYK model, contain polynomial verifiable quantum states in their low energy regime and may be simpler than general local Hamiltonians if UniqueQMA ≠ QMA.