arXiv subjects

Vadim Ponomarenko

Publications and source records attributed to Vadim Ponomarenko.

31 records · Page 2Linked to original sources

arXiv2010

The Renyi-Ulam pathological liar game with a fixed number of lies

The $q$-round Renyi-Ulam pathological liar game with $k$ lies on the set $[n]:=\{1,...,n\}$ is a 2-player perfect information zero sum game. In each round Paul chooses a subset $A\subseteq [n]$ and Carole either assigns 1 lie to each element of $A$ or to each element of $[n]\setminus A$. Paul wins if after $q$ rounds there is at least one element with $k$ or fewer lies. The game is dual to the original Renyi-Ulam liar game for which the winning condition is that at most one element has $k$ or fewer lies. We prove the existence of a winning strategy for Paul to the existence of a covering of the discrete hypercube with certain relaxed Hamming balls. Defining $F^*_k(q)$ to be the minimum $n$ such that Paul can win the $q$-round pathological liar game with $k$ lies and initial set $[n]$, we find $F^*_1(q)$ and $F^*_2(q)$ exactly. For fixed $k$ we prove that $F_k^*(q)$ is within an absolute constant (depending only on $k$) of the sphere bound, $2^q/\binom{q}{\leq k}$; this is already known to hold for the original Renyi-Ulam liar game due to a result of J. Spencer.

math.CO↗

arXiv2004

Antidot tunneling between Quantum Hall liquids with different filling factors

We consider tunneling through two point contacts between two edges of Quantum Hall liquids of different filling factors $ν_{0,1}=1/ (2m_{0,1}+1)$ with $m_0-m_1\equiv m>0$. Properties of the antidot formed between the point contacts in the strong-tunneling limit are shown to be very different from the $ν_0 =ν_1$ case, and include vanishing average total current in the two contacts and quasiparticles of charge $e/m$. For $m>1$, quasiparticle tunneling leads to non-trivial $m$-state dynamics of effective flux through the antidot which restores the regular ``electron'' periodicity of the current in flux despite the fractional charge and statistics of quasiparticles.

cond-mat.mes-hall↗

arXiv2002

Broken symmetry, hyper-fermions, and universal conductance in transport through a fractional quantum Hall edge

We have found solution to a model of tunneling between a multi-channel Fermi liquid reservoir and an edge of the principal fractional quantum Hall liquid (FQHL) in the strong coupling limit. The solution explains how the absence of the time-reversal symmetry at high energies due to chiral edge propagation makes the universal two-terminal conductance of the FQHL fractionally quantized and different from that of a 1D Tomonaga-Luttinger liquid wire, where a similar model but preserving the time-reversal symmetry predicts unsuppressed free-electron conductance.

cond-mat.mes-hall↗

arXiv2000

Coulomb drag between one-dimensional conductors

We have analyzed Coulomb drag between currents of interacting electrons in two parallel one-dimensional conductors of finite length $L$ attached to external reservoirs. For strong coupling, the relative fluctuations of electron density in the conductors acquire energy gap $M$. At energies larger than $Γ= const \times v_- \exp (-LM/v_-)/L + Γ_{+}$, where $Γ_{+}$ is the impurity scattering rate, and for $L>v_-/M$, where $v_-$ is the fluctuation velocity, the gap leads to an ``ideal'' drag with almost equal currents in the conductors. At low energies the drag is suppressed by coherent instanton tunneling, and the zero-temperature transconductance vanishes, indicating the Fermi liquid behavior.

cond-mat↗

arXiv1999

Features of renormalization induced by interaction in 1D transport

One-dimensional interacting electrons in a quantum wire connected to reservoirs are studied theoretically. The difference in the Tomonaga-Luttinger interaction constants between the wire (g) and reservoirs $(g_{\infty})$ produces the cross-correlation between the right- and left-going chiral components of the charge density wave field. The low energy asymptotics of this field correlator, which is determined by (g) and $(g_{\infty})$, specifies renormalization of physical quantities. We have found that charge of the carriers in the shot noise is determined by $g_\infty$ (no renormalization for the Fermi liquid reservoirs) at any energy, meanwhile the factor g renormalizing the charge and spin susceptibilities emerges in the threshold structures at some rational fillings.

cond-mat.str-el↗

arXiv1999

Impurity pinning in transport through 1D Mott-Hubbard and spin gap insulators

A low energy crossover (see cond-mat/9711167) induced by Fermi liquid reservoirs in transport through a 1D Mott-Hubbard insulator of finite length $L$ is examined in the presence of impurity pinning. Under the assumption that the Hubbard gap 2M is large enough: $M > T_L \equiv v_c/L$ ($v_c$: charge velocity in the wire) and the impurity backscattering rate $Γ_1 \ll T_L$, the conductance vs. voltage/temperature displays a zero-energy resonance. Transport through a spin gapped 1D system is also described availing of duality between the backscattered current of this system and the direct current of the Mott-Hubbard insulator.

cond-mat↗

arXiv1999

Umklapp scattering in transport through a 1D wire of finite length

Suppression of electron current $ ΔI$ through a 1D channel of length $L$ connecting two Fermi liquid reservoirs is studied taking into account the Umklapp interaction induced by a periodic potential. This interaction opens band gaps at the integer fillings and Hubbard gaps $2m$ at some rational fillings in the infinite wire: $L \to \infty$. In the perturbative regime where $m \ll v_c/L$ ($v_c:$ charge velocity), and for small deviations $δn$ of the electron density from its commensurate values $- ΔI/V$ can diverge with some exponent as voltage or temperature $V,T$ decreases above $E_c=max(v_c/L,v_c δn)$, while it goes to zero below $E_c$. This results in a non-monotonous behavior of the conductance. In the case when the Umklapp interaction creates a large Mott-Hubbard gap $2m \gg T_L $ inside the wire, the transport is suppressed near half-filling everywhere inside the gap except for an exponentially small region of $V,T < T_L exp(-2m/T_L)$.

cond-mat↗

arXiv1998

Transport through a 1D Mott-Hubbard insulator of finite length

Transport through a 1D Mott-Hubbard insulator of a finite length $L$ is studied beyond perturbative approach. At special value of the low energy constant of the interaction we have mapped the problem onto the exactly solvable models and found current vs. voltage $V$ at high temperature $T>max(m,T_L)$ and at low energy $T,V<T_L$ ($T_L=v_c/L$; $v_c:$ charge velocity). The result shows that for the strong interaction creating a large Mott-Hubbard gap $2m \gg T_L $ inside the wire, the transport is suppressed near half-filling everywhere inside the gap except for an exponentially small region of $V,T < T_L exp(-2m/T_L)$.

cond-mat↗

arXiv1998

Fractional charge in transport through a 1D correlated insulator of finite length

Transport through a one channel wire of length $L$ confined between two leads is examined when the 1D electron system has an energy gap $2M$: $M > T_L \equiv v_c/L$ induced by the interaction in charge mode ($v_c$: charge velocity in the wire). In spinless case the transformation of the leads electrons into the charge density wave solitons of fractional charge $q$ entails a non-trivial low energy crossover from the Fermi liquid behavior below the crossover energy $T_x \propto \sqrt{T_L M} e^{-M /[T_L(1-q^2)]}$ to the insulator one with the fractional charge in current vs. voltage, conductance vs. temperature, and in shot noise. Similar behavior is predicted for the Mott insulator of filling factor $ν= integer/(2 m')$.

cond-mat↗

arXiv1997

From Tomonaga-Luttinger to Fermi liquid in transport through a tunneling barrier

Finite length of a one channel wire results in crossover from a Tomonaga-Luttinger to Fermi liquid behavior with lowering energy scale. In condition that voltage drop $(V)$ mostly occurs across a tunnel barrier inside the wire we found coefficients of temperature/voltage expansion of low energy conductance as a function of constant of interaction, right and left traversal times. At higher voltage the finite length contribution exhibits oscillations related to both traversal times and becomes a slowly decaying correction to the scale-invariant $V^{1/g-1}$ dependence of the conductance.

cond-mat↗

arXiv1997

Threshold features in transport through a 1D constriction

Suppression of electron current $ ΔI$ through a 1D channel of length $L$ connecting two Fermi liquid reservoirs is studied taking into account the Umklapp electron-electron interaction induced by a periodic potential. This interaction causes Hubbard gaps $E_H$ for $L \to \infty$. In the perturbative regime where $E_H \ll v_c/L$ ($v_c:$ charge velocity), and for small deviations $δn$ of the electron density from its commensurate values $- ΔI/V$ can diverge with some exponent as voltage or temperature $V,T$ decreases above $E_c=max(v_c/L,v_c δn)$, while it goes to zero below $E_c$. This results in a nonmonotonous behavior of the conductance.

cond-mat.str-el↗

arXiv1995

Kondo resonance in the case of strong Coulomb screening

The effect of Coulomb screening on the magnetic impurity behavior is analysed. Two types of the behavior corresponding to either integer or fractional occupation numbers of the low lying magnetic level are described. The features in the dependence of the resistivity on the magnetic field specific for these regimes are predicted.

cond-mat↗

arXiv1995

Is there a renormalization of the 1D conductance in Luttinger Liquid model?

Properties of 1D transport strongly depend on the proper choice of boundary conditions. It has been frequently stated that the Luttinger Liquid (LL) conductance is renormalized by the interaction as $g \frac{e^2} {h} $. To contest this result I develop a model of 1D LL wire with the interaction switching off at the infinities. Its solution shows that there is no renormalization of the universal conductance while the electrons have a free behavior in the source and drain reservoirs.

cond-mat↗