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Tom Wong

@thomaswong.net
31 followers 28 following 61 posts

Physics professor at Creighton University. Quantum computing researcher. Views my own.

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Tom Wong @thomaswong.net · 09/10/2026
Today in #PHY131 #QuantumForEveryone: A semiconductor's conductance can be modified by adding atoms with less or more of valence electrons, called p- and n-type doping. Putting both types together creates a p-n junction, which is used for solar panels and is also a diode.
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Tom Wong @thomaswong.net · 09/10/2026
This past Tuesday in #PHY131 #QuantumForEveryone: In the internal photoelectric effect, light excites a bonded electron, making it mobile and decreasing the semiconductor's resistance. The semiconductor is a photoresistor, which a night light uses to detect when it's dark.
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Tom Wong @thomaswong.net · 09/10/2026
Yesterday in #PHY201 #GenPhys1: A box is moved some distance by several forces, including yours (F). The work you did is the component of your force along the direction of movement (Fcosθ), times the distance. Your perpendicular component (Fsinθ) didn't contribute to the work.
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Tom Wong @thomaswong.net · 07/10/2026
Last time in #PHY531 #QuantumMechanics: The scattering states of a delta function well have the same reflection and transmission coefficients as the delta function well. It has one bound state corresponding to decaying exponentials on each side.
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Tom Wong @thomaswong.net · 02/10/2026
Today in #PHY201 #GenPhys1: Static friction has strength up to the coefficient of static friction (μₛ) times the normal force (N). Beyond that, it slips, and kinetic friction is μₖN. Objects in circular motion have centripetal acceleration.
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Tom Wong @thomaswong.net · 01/10/2026
Today in #PHY131 #QuantumForEveryone: When atoms are near, their orbitals overlap, interfere constructively or destructively, and yield molecular orbitals and energy levels. With many atoms, the levels form bands. The bandgap yields conductors, insulators, and semiconductors.
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Tom Wong @thomaswong.net · 30/09/2026
Today in #PHY531 #QuantumMechanics: (1) The group velocity of a wave packet equals the classical particle's speed, while the phase velocity is half. (2) Bound states have normalizable eigenfunctions indexed by discrete n. Scattering states are unnormalized w/ continuous k.
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Tom Wong @thomaswong.net · 30/09/2026
Lately in #PHY201 #GenPhys1: Applications of Newton's 2nd Law involving the normal force, inclines, multiple objects, and tension.
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Tom Wong @thomaswong.net · 30/09/2026
This ice water at Creighton sounds so fancy.
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Tom Wong @thomaswong.net · 29/09/2026
Today in #PHY131 #QuantumForEveryone: A trapped wave has stable ways it can wiggle. A wave on a string or electron in a box has standing waves. An electron trapped by a nucleus (i.e., an atom) has orbitals. Molecular bonding is explained by the interference of orbitals.
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Tom Wong @thomaswong.net · 28/09/2026
Today in #PHY531 #QuantumMechanics: The initial wave function can be expressed as weighted sum of the eigenfuctions of the Hamiltonian, which for the free particle is an integral and inverse Fourier transform. So, the weights are the Fourier transform of the initial state.
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Tom Wong @thomaswong.net · 28/09/2026
Today in #PHY531 #QuantumMechanics: Student: "God, please give me a sine." Me: "Best He can do is a cosine."
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Tom Wong @thomaswong.net · 25/09/2026
Today in #PHY531 #QuantumMechanics: For the quantum harmonic oscillator, the raising and lower operators are Hermitian conjugates of each other. Using this, we can determine the normalization constant when finding eigenfunctions by raising and lowering, resulting in this ladder:
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Tom Wong @thomaswong.net · 25/09/2026
Today in #PHY131 #QuantumForEveryone: Wave-particle duality isn't just a curiosity, it's useful! Microscopes with smaller wavelengths have higher resolution, and microscopes using electrons can have resolutions five orders of magnitude greater than visible light. toutestquantique.fr/en/transmiss...
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Tom Wong @thomaswong.net · 23/09/2026
Today in #PHY531 #QuantumMechanics: The Hamiltonian for the quantum harmonic oscillator can be written in terms of raising and lower operators. Applying them to an eigenfunction yields a new eigenfunction with eigenenergy ℏω higher or lower. Lowering the ground state yields 0.
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Tom Wong @thomaswong.net · 23/09/2026
Creighton is now a top 100 national university! www.creighton.edu/news/creight...
creighton.edu
Creighton named a top 100 national university
Creighton is recognized as a top 100 national university, affirming its long-standing tradition of academic excellence, student success and strong outcomes.
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Tom Wong @thomaswong.net · 23/09/2026
Today in #PHY201 #GenPhys1: Near the surface of the earth, the force of gravity is mg, which is weight. Objects resting on a surface experience a normal force perpendicular to the surface, and it could be equal to, greater than, or less than the weight depending on the situation.
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Tom Wong @thomaswong.net · 23/09/2026
Yesterday in #PHY131 #QuantumForEveryone: Precision timekeeping via atomic clocks enabled the first picture of a black hole by synchronizing radio telescopes across the earth. It also makes GPS possible using the time between GPS signals being sent and received.
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Tom Wong @thomaswong.net · 22/09/2026
Today in #PHY201 #GenPhys1: The first exam, covering units, 1D kinematics, vectors, and 2D kinematics.
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Tom Wong @thomaswong.net · 22/09/2026
The European Union ambassador to the United States, Jovita Neliupšienė @euambus.bsky.social, is speaking at Creighton!
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Tom Wong @thomaswong.net · 21/09/2026
Today in #PHY531 #QuantumMechanics: The eigenfunctions of the quantum harmonic oscillator are Hermite polynomials times a Gaussian. Classically, a particle is confined to a spatial region, but quantumly, it has a nonzero probability of being found outside this region.
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Tom Wong @thomaswong.net · 18/09/2026
Today in #PHY531 #QuantumMechanics: For the quantum harmonic oscillator, energy eigenfunctions are only normalizable at certain discrete energies. Its power series is unnormalizable if the series is infinite, so it terminates as a polynomial, where the order n gives E = (n+½)ℏω.
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Tom Wong @thomaswong.net · 17/09/2026
Today in #PHY131 #QuantumForEveryone: The second used to be defined by the earth's motion. Now it's the time for 9,192,631,770 cycles of a microwave light that excites cesium atoms. Such atomic clocks also define the meter and enable the internet, stock trading, & power grid.
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Tom Wong @thomaswong.net · 17/09/2026
Today in #PHY531 #QuantumMechanics: We began solving the quantum harmonic oscillator using the familiar power series method. After, we'll use a new algebraic method. They will yield the same results here, but when we do angular momentum, they won't!
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Tom Wong @thomaswong.net · 16/09/2026
Today in #PHY201 #GenPhys1: Newton's laws. 1st: In inertial ref frames, objects with zero net force don't accelerate. 2nd: Net force equals mass times acceleration. 3rd: If you push or pull on something, it pushes or pulls back with the same force, but the opposite direction.
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Tom Wong @thomaswong.net · 16/09/2026
Yesterday in #PHY131 #QuantumForEveryone: Lasers are one of the most important inventions of the 20th century. It uses stimulated emission to create more and more coherent photons that are released as a collimated monochromatic beam.
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Tom Wong @thomaswong.net · 14/09/2026
Today in #PHY531 #QuantumMechanics: The first midterm, covering the statistical nature of the wave function through the particle in a box. Here's the first question:
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Tom Wong @thomaswong.net · 14/09/2026
Today in #PHY201 #GenPhys1: If I drive in a circle at a constant speed, my velocity is changing because my direction is changing. So, I have an acceleration--centripetal acceleration--that points toward the center of the circle, even though I'm not speeding up or slowing down.
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Tom Wong @thomaswong.net · 12/09/2026
The Fields Medal is often described as the "Nobel Prize of Mathematics." Twenty-five Fields Medalists have signed an joint statement about "A Severe Misalignment of AI in Mathematics." mathandai.org
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Tom Wong @thomaswong.net · 11/09/2026
Yesterday in #PHY131 #QuantumForEveryone: Each atom's spectra is like a barcode or fingerprint that uniquely identifies the element. They are why neon signs and fireworks are different colors. In spectroscopy, an object's spectrum determines what it is made of and how it moves.
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Tom Wong @thomaswong.net · 10/09/2026
My *third* paper with undergraduate student Jonas Duda is out! In "Faster Computation with the Generalized Laplacian Quantum Walk," we give a quantum walk that outperforms typical quantum walks at a search problem and solves it optimally. arxiv.org/abs/2609.10429
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Tom Wong @thomaswong.net · 09/09/2026
Today in #PHY531 #QuantumMechanics: A particle trapped in a box with initial wave function equal to an upside-down parabola has a probably density that evolves as shown in the animation.
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Tom Wong @thomaswong.net · 09/09/2026
Today in #PHY201 #GenPhys1: In projectile motion, there is constant velocity in the x-direction (with two equations) and constant acceleration in the y-direction (with four equations).
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Tom Wong @thomaswong.net · 09/09/2026
Today in #PHY131 #QuantumForEveryone: We made spectrometers and saw that only certain colors are emitted from each element. The Bohr model of the atom explains this by restricting electrons to discrete shells. Electrons absorb and emit photons to jump up and fall down.
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Tom Wong @thomaswong.net · 05/09/2026
Today in #PHY531 #QuantumMechanics: Say a particle in a box has an initial wave function that's an upside-down parabola. Expressing it as a linear combination of the eigenstates of the Hamiltonian, which are sines, is finding its Fourier series.
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Tom Wong @thomaswong.net · 04/09/2026
One of my students drew a picture on their homework. #PHY531 #QuantumMechanics
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Tom Wong @thomaswong.net · 04/09/2026
New paper with postdoc/mathematician Yujia Shi! By adjusting the strength of a nonlinear quantum walk, we can selectively trap and release a particle, which allows timing in state transfer or use as a quantum memory. doi.org/10.1088/1402...
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Tom Wong @thomaswong.net · 03/09/2026
Today in #PHY131 #QuantumForEveryone: Einstein explained the photoelectric effect, where light ejects electrons from a metal, by proposing that Planck's quantized energies correspond to particles, now called photons. The effect is the basis for image intensification night vision.
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Tom Wong @thomaswong.net · 03/09/2026
Yesterday in #PHY531 #QuantumMechanics: The stationary states of a particle in a box are sine functions, which go to zero at the ends of the box. Their various wavelengths give rise to different energies, which are spaced quadratically apart.
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Tom Wong @thomaswong.net · 02/09/2026
Today in #PHY201 #GenPhys1: Ignoring air resistance, objects near the surface of the earth feel an acceleration due to gravity of -9.8 m/s^2, regardless of the mass of the object. This is constant acceleration, so we can use the kinematic equations for such "free fall" problems.
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Tom Wong @thomaswong.net · 01/09/2026
Today in #PHY131 #QuantumForEveryone: Planck explained blackbody radiation by proposing a quantum of energy = hf. Applications: (1) Blackbody radiation explains why people emit infrared light, which thermal imaging picks up. (2) Planck's constant defines the kilogram.
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Tom Wong @thomaswong.net · 31/08/2026
Today in #PHY531 #QuantumMechanics: Schrödinger's equation is a PDE. If the potential is time independent, it separates into two ODEs. One yields a complex exponential in time. The other is the time-independent Schrödinger equation, an eigenvalue relation for the Hamiltonian.
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Tom Wong @thomaswong.net · 31/08/2026
Today in #PHY201 #GenPhys1: Acceleration is the rate of change of velocity. Assuming acceleration is constant, we derived four kinematic equations which have different combinations of variables.
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Tom Wong @thomaswong.net · 31/08/2026
"Improving Student Self-Confidence in Quantum Computing with the Qubit Touchdown Board Game" is now published in the September issue of The Physics Teacher as an Editor's Pick! doi.org/10.1119/5.02...
doi.org
Improving Student Self-Confidence in Quantum Computing with the Qubit Touchdown Board Game
Qubit Touchdown is a two-player competitive board game that was developed to introduce students to quantum computing. A quantum computer is a new kind of comput
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Tom Wong @thomaswong.net · 28/08/2026
Today in #PHY531 #QuantumMechanics: The expected value of a quantity Q(x,p) is found by replacing p with its operator, sandwiching Q between Ψ* and Ψ, and integrating. The spread of position and momentum measurements of identically prepared systems satisfy Heisenberg's uncertainty principle.
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Tom Wong @thomaswong.net · 28/08/2026
I've been using a refillable dry erase marker for #PHY531 #QuantumMechanics, which only last 1.75 lectures. I mentioned bringing a second marker, and a student said, "It's faster to switch to your secondary than refill your primary." That earned a laugh and a tweet.
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Tom Wong @thomaswong.net · 27/08/2026
Today in #PHY131 #QuantumForEveryone: Students shined lasers through two slits and saw bright and dark fringes, corresponding to constructive and destructive interference, so light is a wave. It's an electromagnetic wave, and different wavelengths have different names and uses.
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Tom Wong @thomaswong.net · 27/08/2026
Yesterday in #PHY531 #QuantumMechanics: For a plane wave to satisfy the Einstein and de Broglie relations, energy and momentum are differential operators. The Hamiltonian equals the total energy, and we get Schrödinger's equation. A normalized wave function stays normalized.
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Tom Wong @thomaswong.net · 26/08/2026
Today in #PHY201 #GenPhys1: If I walk 2 m right and 3 m left, how far did I travel? Two possible answers: (1) 5 m is distance, a scalar. (2) -1 m is displacement, a vector. Velocity is the slope of a position vs time graph, and speed its magnitude.
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Tom Wong @thomaswong.net · 25/08/2026
Today in #PHY131 #QuantumForEveryone: National quantum initiatives and strategies, and the 2025 International Year of Quantum Science and Technology, signify a strong commitment to the field by governments. Only ~half of jobs at quantum companies necessitate technical expertise.
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