Quantum Physics Commons^™

Measurement Of The Half-Life Of The T=1/2 Mirror Decay Of Ne-19 And Its Implication On Physics Beyond The Standard Model, Leah J. Broussard, Henning O. Back, Mitzi S. Boswell, A. S. Crowell, Peter Dendooven, G. S. Giri, Calvin R. Howell, M. F. Kidd, Klaus Jungmann, Wilbert L. Kruithof, A. Mol, Cornelis J. G. Onderwater, Robert W. Pattie Jr., Praveen D. Shidling, M. Sohani, D. J. Van Der Hoek, A. Rogachevskiy, Emil Traykov, Oscar O. Versolato, Lorenz Willmann, Hans W. Wilschut, Andrew T. Young

Robert W. Pattie Jr.

Implications Of The Landauer Limit For Quantum Logic, F. Matthew Mihelic

Faculty Publications

The design of any system of quantum logic must take into account the implications of the Landauer limit for logical bits. Useful computation implies a deterministic outcome, and so any system of quantum computation must produce a final deterministic outcome, which in a quantum computer requires a quantum decision that produces a deterministic qubit. All information is physical, and any bit of information can be considered to exist in a physicality represented as a decision between the two wells of a double well potential in which the energy barrier between the two wells must be greater than kT·ln2. Any proposed …

A Cavity-Cooper Pair Transistor Scheme For Investigating Quantum Optomechanics In The Ultra-Strong Coupling Regime, A. J. Rimberg, M. P. Blencowe, A. D. Armour, P. D. Nation

Dartmouth Scholarship

We propose a scheme involving a Cooper pair transistor (CPT) embedded in a superconducting microwave cavity, where the CPT serves as a charge tunable quantum inductor to facilitate ultra-strong coupling between photons in the cavity and a nano- to meso-scale mechanical resonator. The mechanical resonator is capacitively coupled to the CPT, such that mechanical displacements of the resonator cause a shift in the CPT inductance and hence the cavity's resonant frequency. The amplification provided by the CPT is sufficient for the zero point motion of the mechanical resonator alone to cause a significant change in the cavity resonance. Conversely, a …

Schrödinger And Nietzsche And Life: Eternal Recurrence And The Conscious Now, Babette Babich

Articles and Chapters in Academic Book Collections

The phenomenological question of consciousness usually associated with Husserl (although there are echoes of this in Augustine as in Marcus Aurelius, Kant and Schopenhauer), is the consciousness of the now, the present moment. I explore this consciousness for Erwin Schrödinger, which for him included reference to the Upaniṣads together with Nietzsche’s central teaching or “thinking” of the eternal recurrence of the same.

Exact And Approximate Solutions For The Quantum Minimum-Kullback-Entropy Estimation Problem, Carlo Sparaciari, Stefano Olivares, Francesco Ticozzi, Matteo G. A. Paris

Dartmouth Scholarship

The minimum-Kullback-entropy principle (mKE) is a useful tool to estimate quantum states and operations from incomplete data and prior information. In general, the solution of an mKE problem is analytically challenging and an approximate solution has been proposed and employed in different contexts. Recently, the form and a way to compute the exact solution for finite dimensional systems has been found, and a question naturally arises on whether the approximate solution could be an effective substitute for the exact solution, and in which regimes this substitution can be performed. Here, we provide a systematic comparison between the exact and the …

Majorana Flat Bands In S -Wave Gapless Topological Superconductors, Shusa Deng, Gerardo Ortiz, Amrit Poudel, Lorenza Viola

Dartmouth Scholarship

We demonstrate how the nontrivial interplay between spin-orbit coupling and nodeless s-wave superconductivity can drive a fully gapped two-band topological insulator into a time-reversal invariant gapless topological superconductor supporting symmetry-protected Majorana flat bands. We characterize topological phase diagrams by a Z2×Z2 partial Berry-phase invariant, and show that, despite the trivial crystal geometry, no unique bulk-boundary correspondence exists. We trace this behavior to the anisotropic quasiparticle bulk gap closing, linear vs quadratic, and argue that this provides a unifying principle for gapless topological superconductivity. Experimental implications for tunneling conductance measurements are addressed, relevant for lead chalcogenide materials.

Hamiltonian Quantum Simulation With Bounded-Strength Controls, Adam D. Bookatz, Pawel Wocjan, Lorenza Viola

Dartmouth Scholarship

We propose dynamical control schemes for Hamiltonian simulation in many-body quantum systems that avoid instantaneous control operations and rely solely on realistic bounded-strength control Hamiltonians. Each simulation protocol consists of periodic repetitions of a basic control block, constructed as a modification of an 'Eulerian decoupling cycle,' that would otherwise implement a trivial (zero) target Hamiltonian. For an open quantum system coupled to an uncontrollable environment, our approach may be employed to engineer an effective evolution that simulates a target Hamiltonian on the system while suppressing unwanted decoherence to the leading order, thereby allowing for dynamically corrected simulation. We …

The Problem Of Confirmation In The Everett Interpretation, Emily Adlam

Mathematics, Physics, and Computer Science Faculty Articles and Research

I argue that the Oxford school Everett interpretation is internally incoherent, because we cannot claim that in an Everettian universe the kinds of reasoning we have used to arrive at our beliefs about quantum mechanics would lead us to form true beliefs. I show that in an Everettian context, the experimental evidence that we have available could not provide empirical confirmation for quantum mechanics, and moreover that we would not even be able to establish reference to the theoretical entities of quantum mechanics. I then consider a range of existing Everettian approaches to the probability problem and show that they …

Quantum Optics Of Polaritonic Nanocomposites, Chris Racknor

Electronic Thesis and Dissertation Repository

In this thesis, we study the quantum optical interaction in polaritonic nanocomposites. These systems are made by the combination of two or more micro- or nano-scale structures with complementary optical properties, such as polaritonic materials, excitonic materials, photonic crystals (PCs), quantum dots (QDs), waveguides, couplers, metal nanorods (MNRs), bionanoparticles. The nanocomposites systems studied included QDs doped within a polaritonic PC, an excitonic waveguide coupler, and a metamaterial waveguide. Also addressed are systems consisting of MNRs paired with biological labelling dye or QDs.

The application of a strain field, known as the acousto-optic effect, was found to control photon transmission in …

Studies Of Charge Collection In Diamond-Based Particle Detectors At The Lhc, Jared Smith

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

See file

Three-Point Current Correlation Functions As Probes Of Effective Conformal Theories, Kassahun Betre

Faculty Publications

See abstract in PDF.

Dipole Bound Excited States Of Polycyclic Aromatic Hydrocarbons Containing Nitrogen And Their Relation To The Interstellar Medium, Mallory L. Theis

Honors College Theses

Polycyclic aromatic hydrocarbons (PAHs) are the most abundant type of molecule present in the interstellar medium (ISM). It has been hypothesized that nitrogen replacement within a ring is likely for PAHs present in the ISM. Additionally, electrons, protons, and hydrogen atoms are readily added to or removed from PAHs creating a truly diverse set of chemistries in various interstellar regions. The presence of a nitrogen within a PAH (called a PANH herein) that is additionally dehydrogenated leads to a neutral radical with a large dipole moment. It has recently been shown through the use of high-level quantum chemical computations for …

Colloquium: Understanding Quantum Weak Values: Basics And Applications, Justin Dressel, Mehul Malik, Filippo M. Miatto, Andrew N. Jordan, Robert W. Boyd

Mathematics, Physics, and Computer Science Faculty Articles and Research

Since its introduction 25 years ago, the quantum weak value has gradually transitioned from a theoretical curiosity to a practical laboratory tool. While its utility is apparent in the recent explosion of weak value experiments, its interpretation has historically been a subject of confusion. Here a pragmatic introduction to the weak value in terms of measurable quantities is presented, along with an explanation for how it can be determined in the laboratory. Further, its application to three distinct experimental techniques is reviewed. First, as a large interaction parameter it can amplify small signals above technical background noise. Second, as a …

Magnetic Fields In An Expanding Universe, David Kastor, Jennie Traschen

David Kastor

We find a solution to 4D Einstein-Maxwell theory coupled to a massless dilaton field describing a Melvin magnetic field in an expanding universe with 'stiff matter' equation of state parameter w=+1. As the universe expands, magnetic flux becomes more concentrated around the symmetry axis for dilaton coupling a<1/3√ and more dispersed for a>1/3√. An electric field circulates around the symmetry axis in the direction determined by Lenz's law. For a=0 the magnetic flux through a disk of fixed comoving radius is proportional to the proper area of the disk. This result disagrees with the usual expectation based on a test magnetic field that this …

Classical Field Approach To Quantum Weak Measurements, Justin Dressel, Konstantin Y. Bliokh, Franco Nori

Mathematics, Physics, and Computer Science Faculty Articles and Research

By generalizing the quantum weak measurement protocol to the case of quantum fields, we show that weak measurements probe an effective classical background field that describes the average field configuration in the spacetime region between pre- and postselection boundary conditions. The classical field is itself a weak value of the corresponding quantum field operator and satisfies equations of motion that extremize an effective action. Weak measurements perturb this effective action, producing measurable changes to the classical field dynamics. As such, weakly measured effects always correspond to an effective classical field. This general result explains why these effects appear to be …

Monitoring Atom Traps For Neutral Atom Quantum Computing, Taylor Shannon

Physics

To increase computing power for numerous practical advantages, scientists are actively researching the field of quantum computing. Neutral atom quantum computing is a promising avenue towards building a quantum computer that satisfies four of the five DiVincenzo criteria. This involves a magneto-optical trap to cool the atoms and move them to a cloud in the center of a vacuum chamber. Then laser light will be shone through an array of pinholes to trap the atoms in an array of dipole traps. In order to ensure the atoms are trapped, I have set up an imaging system that consists of a …

Developing A Diffraction Pattern Projection System For Neutral Atom Quantum Computation, Sanjay Khatri

Physics

No abstract provided.

Spannungsfeld, Julian Voss-Andreae

The STEAM Journal

My design for a sculptural installation for the University of Minnesota’s new Physics and Nanotechnology Building is inspired by a view of the human body through the lens of quantum physics.

The German title of the installation (literally "tension field") originated in physics but is used in contemporary German almost exclusively in a metaphorical sense, implying a dynamic tension, often between polar opposites, that permeates everything in its vicinity.

Session D-4: Teaching Quantum Mechanics, Peter Dong

Professional Learning Day

Quantum mechanics is a part of modern life, playing a major role in chemistry, computing, nanotechnology, cryptography, and even biology. Many students are fascinated by the principles of quantum mechanics - and wave-particle duality is now in the Next Generation Science Standards. This course will present a basic introduction to quantum mechanics, accessible to middle or high school students, that will give students a taste of how strange and wonderful the universe really is (while also meeting the new standard). Teachers will be given slides and materials so they can teach the lesson themselves.

Composite Fermions And Integer Partitions, Arthur Benjamin, Jennifer Quinn, John Quinn, Arkadiusz Wojs

Jennifer J. Quinn

We utilize the KOH theorem to prove the unimodality of integer partitions with at most a parts, all parts less than or equal to b, that are required to contain either repeated or consecutive parts. We connect this result to an open question in quantum physics relating the number of distinct total angular momentum multiplets of a system of N fermions, each with angular momentum ℓ, to those of a system in which each Fermion has angular momentum ℓ*=ℓ−N+1.

Transformation Of Statistics In Fractional Quantum Hall Systems, John J. Quinn, Arkadiusz Wojs, Jennifer J. Quinn, Arthur T. Benjamin

Jennifer J. Quinn

A Fermion to Boson transformation is accomplished by attaching to each Fermion a tube carrying a single quantum of flux oriented opposite to the applied magnetic field. When the mean field approximation is made in Haldane’s spherical geometry, the Fermion angular momentum lF is replaced by lB =lF − 1/2 (N −1). The set of allowed total angular momentum multiplets is identical in the two different pictures. The Fermion and Boson energy spectra in the presence of many body interactions are identical only if the pseudopotential V (interaction energy as a function of pair angular momentum L12) increases as L12(L12 …

The Fermion–Boson Transformation In Fractional Quantum Hall Systems, John Quinn, Arkadiusz Wojs, Jennifer Quinn, Arthur Benjamin

Jennifer J. Quinn

A Fermion to Boson transformation is accomplished by attaching to each Fermion a single flux quantum oriented opposite to the applied magnetic field. When the mean field approximation is made in the Haldane spherical geometry, the Fermion angular momentum l_F is replaced by l_B - l_F - 1/2(N-1). The set of allowed total angular momentum multiplets is identical in the two different pictures. The Fermion and Boson energy spectra in the presence of many body interactions are identical if and only if the pseudopotential is "harmonic" in form. However, similar low energy bands of states with Laughlin correlations occur in …

Strategies For The Characteristic Extraction Of Gravitational Waveforms, Maria C. Babiuc-Hamilton, N. T. Bishop, B´Ela Szila´Gyi, Jeffrey Winicour

Maria C. Babiuc-Hamilton

We develop, test, and compare new numerical and geometrical methods for improving the accuracy of extracting waveforms using characteristic evolution. The new numerical method involves use of circular boundaries to the stereographic grid patches which cover the spherical cross sections of the outgoing null cones. We show how an angular version of numerical dissipation can be introduced into the characteristic code to damp the high frequency error arising form the irregular way the circular patch boundary cuts through the grid. The new geometric method involves use of the Weyl tensor component Ψ4 to extract the waveform as opposed to the …

Characteristic Extraction Tool For Gravitational Waveforms, Maria C. Babiuc-Hamilton, B´Ela Szila´Gyi, Jeffrey Winicour, Yosef Zlochower

Maria C. Babiuc-Hamilton

We develop and calibrate a characteristic waveform extraction tool whose major improvements and corrections of prior versions allow satisfaction of the accuracy standards required for advanced LIGO data analysis. The extraction tool uses a characteristic evolution code to propagate numerical data on an inner worldtube supplied by a 3+1 Cauchy evolution to obtain the gravitational waveform at null infinity. With the new extraction tool, high accuracy and convergence of the numerical error can be demonstrated for an inspiral and merger of mass M binary black holes even for an extraction worldtube radius as small as R=20M. The tool provides a …

Constraint-Preserving Sommerfeld Conditions For The Harmonic Einstein Equations, Maria Babiuc-Hamilton, H-O. Kreiss, Jeffrey Winicour

Maria Babiuc-Hamilton

The principle part of Einstein equations in the harmonic gauge consists of a constrained system of 10 curved space wave equations for the components of the space-time metric. A new formulation of constraint-preserving boundary conditions of the Sommerfeld-type for such systems has recently been proposed. We implement these boundary conditions in a nonlinear 3D evolution code and test their accuracy.

Certainty In Heisenberg’S Uncertainty Principle: Revisiting Definitions For Estimation Errors And Disturbance, Justin Dressel, Franco Nori

Mathematics, Physics, and Computer Science Faculty Articles and Research

We revisit the definitions of error and disturbance recently used in error-disturbance inequalities derived by Ozawa and others by expressing them in the reduced system space. The interpretation of the definitions as meansquared deviations relies on an implicit assumption that is generally incompatible with the Bell-Kochen-Specker- Spekkens contextuality theorems, and which results in averaging the deviations over a non-positive-semidefinite joint quasiprobability distribution. For unbiased measurements, the error admits a concrete interpretation as the dispersion in the estimation of the mean induced by the measurement ambiguity.We demonstrate how to directly measure not only this dispersion but also every observable moment with …

Solving The Instantaneous Response Paradox Of Entangled Particles Using The Time Of Events Theory, Sadeem Abbas Fadhil

Sadeem Abbas Fadhil

In the present study, a new theory that relates the special theory of relativity with quantum mechanics is formulated and then used to explain the remote instantaneous response of entangled particles without the assumptions of nonlocality or hidden variables. The basic assumptions of the present theory stands on the foundation of two space-times, namely, the static and dynamic space-times, in which the latter contains space points that move at the speed of light. The remote instantaneous interaction of the entangled particles is due to the closeness of these particles to each other in the dynamic space-time in spite of remoteness …

Avoiding Loopholes With Hybrid Bell-Leggett-Garg Inequalities, Justin Dressel, Alexander N. Korotkov

Mathematics, Physics, and Computer Science Faculty Articles and Research

By combining the postulates of macrorealism with Bell locality, we derive a qualitatively different hybrid inequality that avoids two loopholes that commonly appear in Leggett-Garg and Bell inequalities. First, locally invasive measurements can be used, which avoids the “clumsiness” Leggett-Garg inequality loophole. Second, a single experimental ensemble with fixed analyzer settings is sampled, which avoids the “disjoint sampling” Bell inequality loophole. The derived hybrid inequality has the same form as the Clauser-Horne-Shimony-Holt Bell inequality; however, its quantum violation intriguingly requires weak measurements. A realistic explanation of an observed violation requires either the failure of Bell locality or a preparation conspiracy …

Wave Function For Harmonically Confined Electrons In Time-Dependent Electric And Magnetostatic Fields, Hong-Ming Zhu, Jin-Wang Chen, Xiao-Yin Pan, Viraht Sahni

Publications and Research

We derive via the interaction “representation” the many-body wave function for harmonically confined electrons in the presence of a magnetostatic field and perturbed by a spatially homogeneous time-dependent electric field—the Generalized Kohn Theorem (GKT) wave function. In the absence of the harmonic confinement – the uniform electron gas – the GKT wave function reduces to the Kohn Theorem wave function. Without the magnetostatic field, the GKTwave function is the Harmonic Potential Theorem wave function. We further prove the validity of the connection between the GKT wave function derived and the system in an accelerated frame of reference. Finally, we provide …

Quantum Correlations Of Lights In Macroscopic Environments, Yong Meng Sua

Dissertations, Master's Theses and Master's Reports - Open

This dissertation presents a detailed study in exploring quantum correlations of lights in macroscopic environments. We have explored quantum correlations of single photons, weak coherent states, and polarization-correlated/polarization-entangled photons in macroscopic environments. These included macroscopic mirrors, macroscopic photon number, spatially separated observers, noisy photons source and propagation medium with loss or disturbances.

We proposed a measurement scheme for observing quantum correlations and entanglement in the spatial properties of two macroscopic mirrors using single photons spatial compass state. We explored the phase space distribution features of spatial compass states, such as chessboard pattern by using the Wigner function. The displacement and …